Frequently Asked Questions what to do when spring planted plants are not vigorous
AUGUST 2016 GROWING TIPS
Written by Raintree Nursery Horticulturist, Theresa Knutsen
In the July Growing tips, I wrote about the spotted wing drosophila, a recently introduced fruit fly that has been observed along the western seaboard of the U.S. and into Canada, west of the Rocky Mountains. The female fly deposits her eggs in berries and soft fruit as they approach ripening (other fruit flies wait until the fruit is full ripe). It is valuable to put out monitoring traps to determine if this pest is in your back yard. For more information on this new pest and directions to make a monitoring trap go to http://ipm.ucanr.edu/EXOTIC/index.html. Scroll down and select from the articles listed under spotted wind drosophila.
There is another new insect of concern west of the Cascades in the Pacific Northwest, the Brown Marmorated Stink Bug, which has the potential to cause serious fruit damage in soft fruits as well as hazelnuts, vegetables, and ornamentals. It is already established in other parts of the country. While it is not considered to be a major threat at this time, there is enough concern to warrant tracking this insect. For more information go to http://horticulture.oregonstate.edu/group/brown-marmorated-stink-bug-oregon. Todd Murray, of WSU Skamania County Extension, is requesting assistance in monitoring this stink bug which has been observed in Skamania, Clark, and Lewis counties of Washington state. If you would like to help contact him at firstname.lastname@example.org. Another site with lots of information is http://www.stopbmsb.org/ hosted by Cornell University.
APPLE MAGGOT/ CODLING MOTH: Continue monitoring for apple maggot flies and codling moths if using sprays as your control measure. Reapply sprays when the number of flies trapped increases, or if you are using Surround, re-apply when growth of the fruit or rain fall has reduced the white coverage.
Sanitation is an important cultural tool for reducing the over-all insect population of both apple maggot and codling moth, or any other fruit infesting insects in your orchard. Pick up any fruit that falls early in the ripening season (within a couple days of falling) and discard or destroy it, before the developing maggot or larvae is mature enough to crawl out of the fruit and continue its life cycle. The first fruit drops following pollination are the most important to pick up, but cleaning up the fruit in August will help reduce the over-wintering population. The more isolated your orchard is the more effective picking up the fruit will be. If your neighbors are not picking up their fallen fruit you might consider putting up extra monitoring traps between your orchard and theirs, to trap some of the migrating insects before they arrive in your orchard. You can find apple maggot and codling moth traps on our Pest Control page.
Too many codling moth traps in a small orchard can actually increase their population as they are drawn in by the pheromones. Two-three traps are enough for the typical backyard orchard, if needed, place one of those traps between your trees and a potential flight path.
Spinosyn based insecticides, such as Spinosad, a quick acting broad spectrum natural insecticide spray derived from the metabolites of a common soil bacterium, and neem oil based insecticides such as Safer Bioneem Botanical Insecticide are both effective against codling moth, plum curculio, and currant worm caterpillars before they enter the fruit. Use spinosyns for heavier infestations, and follow label instructions on timing to avoid damage to beneficial insects, up to 6 sprays per year. Use neem oil based products when you prefer a more gentle approach. The first spray would be applied 2-4 weeks after bloom, or when you started seeing pin hole scars in the fruit (from the little caterpillars chewing their way into the fruit). Applying spray in August is helpful in controlling second or third generations of these pests. Start looking for the scars a week or so after catching increased numbers of adults in your monitoring traps, when you start seeing new scars it is time to spray.
Some varieties of grapes, apples, gooseberry, currants and other fruiting plants are susceptible to powdery mildew. There are chemical fungicide sprays available at your local nursery, or you may want to try the recipe on page 22 in our Raintree Plant Owner’s manual . You can achieve a reasonable level of control using fatty-acid soap, oil (such as Neem), and powdered milk, but you will need to apply repeated sprays throughout the typical infection period, from June through August or September. To avoid having to spray, choose varieties listed as being resistant or immune to powdery mildew.
Grapes that are born in tight clusters can be susceptible to botrytis (bunch rot). Thin fruit clusters to maintain better air circulation in the bunch. Serenade, a biological fungicide derived from Bacillus subtilis strain, may be effective as a spray. Botrytis also affects other fruits, including strawberry, raspberry, blackberry, blueberry, cherry, and pear. Keeping the fruit dry, and not in contact with other fruit will help minimize spread of the disease. Sanitation is very important. Clean up and discard infected fruit (compost piles are generally not hot enough to destroy the organism), as well as old leaves that have died back or have fungal lesions on them, to remove as much source of innoculum as you can.
STONE FRUITS: Spray cherries, peaches, plums, and other stone fruits with a fungicide for brown rot, botrytis (gray mold) and other fruit infesting fungi if rain threatens or occurs just prior to harvest. Inspect for fruits that are showing evidence of infection, brown water-soaked looking lesions on the surface of the fruit in concentric rings or irregular patches, brown or gray fuzzy dots or patches. Pick and burn or discard infected fruits to help control the spread of fungal diseases. Apple, pear, and quince should also be inspected for possible infections.
Check CAMELLIAS, CITRUS, and other SMOOTH LEAVED EVERGREENS for black sooty growth on leaves and stems. Sooty mold grows on the sugary honeydew secretions of sucking insects (aphid, scale, or mealy bug), turning the leaf surfaces black. You can remove the sooty mold by spraying with the fatty-acid soap / light oil /milk mixture on pg 22 of Raintree Plant Owner's Guide, then wipe or forcefully spray the mold away. Be careful with the water spray, test a few leaves first to be sure you are not damaging them with too hard a spray. This mixture makes the sooty mold easier to remove and kills the sucking insects at the same time. One spray will not be sufficient to fully control the insects, see the Raintree Plant Owners Manual for more information.
* NOTE: Your local co-operative extension office should be able to provide you with pest and disease identification assistance, as well as pesticide and their use recommendations. Look in your local phone book under county listings, or go to our Helpful Links page, in Growers Info in the top tool bar, to find your local office along with other helpful resources.
Install bird netting wherever the birds are getting more of the fruit than you want them to. Grape vines trained in a vertical curtain, pg 12 in our Raintree Plant Owners Guide are easier to stretch our extra wide commercial bird netting (#T431) over. Cherry trees grown on the dwarfing giesela 5 or krymsk 5 rootstock and trained in an open center pattern are also easier to get the netting around. Be sure the netting is securely closed together under the tree or vine canopy, those sneaky birds can find their way up through the inside.
Control weeds and keep grass short around bushes and trees and among recently planted ground covers. Maintain a minimum 3’ diameter circle for each tree or shrub that is free of competing weeds. If there are a lot of weeds coming up in your new groundcover planting, lay multiple layers of newspaper, or a layer of cardboard, between plants to smother weeds and retain soil moisture. A layer of bark or compost on top will keep the area looking nice. Invasive perennial weeds, such as quack grass, ivy, or morning glory will not be controlled as readily in one year with smothering.
Monitor fruit trees, especially those with heavy crops that were not thinned earlier in the season, for drooping branches that look like they could break. There are many this year in the Pacific Northwest, where apple, pear and fig set were pretty heavy. Prune the ends of those drooping branches off, or remove fruit from the ends of the branches, to prevent major limbs from breaking. If you can’t bring yourself to sacrifice some fruit then at least prop up branches with a sturdy brace. Remember, breaks usually cause a lot more damage to the tree than the lighter thinning or pruning would have. Next winter reduce the length of those long thin branches that were drooping this summer, to increase their strength.
This year we have seen a warm dry spring followed by a cool somewhat wet early summer for growers in the Pacific Northwest. Many trees are already showing water stress in spite of those showers. In normal years drought-induced dormancy in the trees often occurs in August, and could be a factor again this year with a typical August increase in temperature and decrease in rainfall. Repeated years of such stress can hamper plant and root system health. Check the soil where stressed plants are growing, cracked dry soil conditions can be corrected next year with coarse organic mulches on the surface and perhaps different irrigation practices. (See the section on irrigation for more information) This year provide a slow deep watering to re-hydrate the soil, (starting just inside the outside edge of the leaf canopy and extending outward several feet) if needed. Last year's drought may have caused some damage to tree root systems, and this year's heavy fruit sets would further stress trees.
Fall flowering of spring flowering plants can occur as a result of summer heat or drought stress induced dormancy, followed by a cool or wet period, fooling the plant into functioning as if spring has just arrived. Don’t worry, not all of next spring’s flower buds will open in the fall.
VINES: Manage the canopy of your vigorous grape vines. As fall approaches it may be desirable to remove some leaves, or shoots, to expose ripening fruit to the sun. Vines can be cut off at the fifth leaf past the last fruit cluster to improve air circulation and sun exposure. Your kiwi vines may also be growing out of control. Cut back any vigorous shoots that are growing over the top of your selected producing side shoots to the point of origin if they are not needed, or to the width of your trellis if you need them to replace or fill in as a fruiting arm. See Growing Kiwifruit (#S240 ) for more information on managing and caring for your kiwi vines.
ESPALIER: Cut back the pinched-out shoots on fan-trained plums (until mid-September). Cut out old fruiting laterals on established fan-trained acid cherries, peaches and nectarines as well after they are done fruiting. Continue maintenance pruning of established pear and apple espalier trees. In the Pacific Northwest the modified Lorette pruning system recommended in the RHS Fruit book may induce late summer bud break lower in the shoot than is preferred, reducing the number of flower buds for next spring. Instead, through August keep vigorous upright shoots controlled by cutting them back to a point about 6“ above where you want fruit buds to initiate. The top buds you leave will grow, with less vigor than the shoot you removed, well above the initiating flower buds you prefer to stay dormant. Next winter cut those vigorous shoots back to the flower buds that have initiated at their base to develop a new fruit spur. The book Pruning and Training-Revised by Brickell and Joyce, (#S325) has excellent line drawings and instructions to help you train and maintain your espaliered fruit tree.
NUTS: Break (brut) vigorous lateral shoots on filberts to about ½ their length and leave them hanging, to help improve air circulation in the tree and ripen next year’s new fruit buds. Thin those same shoots in winter to 3-4 buds. Thin out long thin crowding shoots on established sweet chestnuts and walnuts.
BERRIES: Remove fruiting canes of raspberries and blackberries after all of the fruit has been picked, but leave this year’s new canes to produce fruit next year. If you left the lower portion of your primocane berries last fall then finish removing them this month after you have picked all the fruit they produced, leaving this years’ new canes to produce later this month and into September. Pinch out runners on day-neutral strawberries to focus their energy on continued fruit production. Late July or early August mow over the top of your main season strawberry beds (mower set at highest position) to clean up old leaves and encourage new leaf growth. Remove runners that are crowding the bed, or re-position to a spot in the bed that needs filling in.
FRUIT TREES: Try to finish any summer pruning you have left to do before the latter part of the month, focusing more on thinning cuts. Any new growth that occurs late in August, or later, will tend not to harden off properly before winter settles in, and will then be more susceptible to winter damage.
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During the long hot days of summer irrigate as needed to provide the equivalent of 1” of rain per week (enough water to saturate the soil to 1 foot deep). Irrigation is especially valuable for newly planted trees (1-2 years) whose root systems are not fully established deep into the soil. Mature fruiting trees will also benefit from irrigation in the last few weeks before the fruits are ready to pick. Water in the tree is used to fill and expand the cells in the fruit. Extra water will pump up the fruit so it is large and juicy when you pick. During extreme heat episodes, a little more water than you are accustomed to applying may be needed to reduce signs of heat stress in your trees such as excess early fruit drop, leaf wilt and leaf curl. It is important to provide the water to the portion of the root system that will take it up. Apply the water to saturate the soil from just inside the leaf canopy to several feet beyond the drip line. Avoid wetting the foliage and fruit of fruit trees that are sensitive to brown rot, powdery mildew, and other fungal diseases. Drip irrigation allows you to use less water, keep the foliage dry, and still accomplish the goal of maintaining your trees.
As plants start heading into dormancy later in the month, or early September, you can begin to water less frequently, but don’t let plants get too dry. Plants whose inner or lower leaves turn yellow and drop are likely showing a drought stress response, as oldest leaves are shed when water supply becomes short. If drought becomes severe, early fall color and total leaf drop can occur. A word of caution: These very same symptoms can show up when excess water in the planting hole drowns roots (displaces oxygen from the soil). This can even occur in a well-drained soil, if the soil in the planting hole was significantly modified at planting time. Dig below the surface. If you find waterlogged soil that smells bad, you probably need to correct soil drainage or your watering practices.
The ripening time of a particular fruit varies from one location to another and from year to year, though the order in which varieties ripen stays roughly the same. This year in the Pacific Northwest, with the mild winter and hot spring temperatures we experienced, fruit ripening is currently trending 2-3 weeks early. The ripening times we give on our website in the “How to Grow” sections and in our catalog are relative to the Pacific Northwest where Raintree Nursery is located. Use the Raintree ripening order charts as a guide to know when to start checking your fruit.
Here are some hints to help you know when typically August ripening fruit in your orchard are ready to pick, from ‘usuals’ to ‘unusuals’:
Figs are ready when the fruit fully droops from its own weight and is soft. Desert King is particularly rich tasting if you wait until the skin takes on a brown gnarly look.
Sea buckthorn, when the fruit is soft and you no longer taste the astringency, can be harvested by cutting whole branches, then work the fruit off the branches into a bowl. Use the juice to make jellies, syrups, or to mix with other juices. The raw fruit and juice are not recommended for fresh consumption in large quantity, the high vit C content can cause nausea.
Cornus mas, harvest when the fruits readily drop from the tree, are soft, and no longer astringent. Yellow fruited are translucent and incredibly sweet when ready to eat. The fruit tends to ripen unevenly, so check your bush regularly. Laying a ground cloth down and shaking the bush to loosen the ready fruit can work. Or harvest the berries at the firm ripe stage when they have turned from orange to red (or from white to yellow in the case of the yellow fruited), but are still firm; they will finish ripening off the bush at room temperature. Process berries that are soft when harvested right away, they don’t store well. The red varieties vary in flavor, and are usually preferred for cooking, rather than fresh eating.
Aronia produce copious quantities of blue-black fruits that are usually ready to pick in late summer. Until the berries have started to soften the fruit will be astringent. Aronia are not considered a fresh eating fruit, use to make jam, or juice and make jelly or mixed fruit juice beverages. The leftover mixed pulp can be mixed with applesauce for fruit leathers or butter. I like to use my lingonberry rake (#T300) to harvest the berries, so I can get the job done a lot quicker.
Goumi are another fruit that is typically used for cooking, not fresh eating. Berries are astringent until soft, ripen unevenly, and easily fall from the bush when full ripe. Like the Cornus mas above, you could lay a ground cloth down and shake the bush to release berries that are ready. I’ve noticed the birds are quite fond of our berries here; it’s getting harder for me to harvest enough to do anything. Note that these berries have pits so be careful when you bite into one. See our recipes page for tips on getting the best flavored juice.
Kolomikta kiwi, the first of the kiwi to ripen and one of the sweetest. The fruit are small but numerous. Pick when the fruit is firm ripe (berry feels firm, but when you cut it open the seeds inside are mature, dark brown in color), and store in a cool place. Finish ripening the fruit in a warm area when you are ready to eat it. Or pick regularly as the fruit finish ripening unevenly on the vine. The berries can be eaten fresh, and made into jam, jelly, or dried like a raisin.
Early ripening European and Asian pears. European pears are harvested while still green and kept in a cool place for a few days or several months, depending on the variety, to allow the outer portion of the fruit to catch up with the ripening of the core. Earlier maturing varieties tend to need less storage time and may even be in good condition if left on the tree until full ripe (core not over-ripe and starting to rot). Fruit is ready to pick when the stem readily separates from the tree as you bend the fruit upwards. Asian pears do not continue ripening after they have been picked, so leave them on the tree until they are fully ripe. One of my favorite ways to judge them is to gently poke my thumbnail into the skin of the fruit. If I readily pierce the skin it is generally ready, if the skin is still tough then it is not ready. Or, when the background color of the part of the fruit facing away from the sun changes from green to yellow and the fruit releases from the stem easily. If your trees do not receive enough summer heat or water, the fruit may not develop much flavor or sweetness, even though it appears to be ripe.
Early ripening European and Asian plums. Early Laxton is the earliest of the European plums we offer to ripen, about the same time as the Asians Early Golden, Beauty, Methley, Santa Rosa, and certain Asian x American crosses, such as the Kuban series. Opinions vary as to when plums are ready to eat, I like to let them start softening, especially Methley and Beauty with their high water content. Others like them more green and tart. The ripening times we give in our catalog are relative to the Pacific Northwest. In your location, and even in certain years, ripening times may vary.
Early Apple varieties, such as Centennial, Pristine, and Williams Pride, are often ready to start picking by mid-August. Again, some people like their fruit more green and tart, others more ripe. When you cut the fruit open and look at the seed color, dark brown indicates the seed and the fruit are mature. Varieties like Pristine, or Chehalis (next month) are considered best a little on the green side, turning soft and starchy as the skin turns yellow. Early ripening apples tend to not last long on the tree, expect to harvest all of the fruit within 10-14 days after the fruit is ready to eat. Applesauce is a great way to make use of all that fruit ripening at once. A Fruit Strainer and Sauce Maker (#T385) will help you get the job done quickly. Use it also to make seedless blackberry or mulberry pulp for jam or fruit leathers.
Berries. Enjoy everbearing strawberries, late ripening blackberries, loganberries, blueberries and fall-fruiting raspberries.
Elderberries will be ripening soon for you to make juices, wines, and jellies from. The fruits are ready to harvest when they are blue/black and juicy. Clip clusters of berries when they are ready, a pole pruner will make it easier to reach the clusters of the taller growing blue elderberry. Do not consume a quantity of raw elderberry, cooking destroys the molecule that would otherwise cause gastric distress.
Peaches, Nectarines, and Apricots are harvested when the background color of the part of the fruit facing away from the sun changes from green to yellow and the fruit comes off the stem easily. The rest of the fruit may have varying degrees of red or gold, depending on the fruit you are harvesting and the amount of sun exposure on the fruit. The fruit should also be aromatic. Once picked the fruit will continue to soften; eat, can, freeze, or dry the fruit when it has reached the texture you prefer. In the Pacific Northwest July (east of the cascades) and August (west of the cascades) are typical months for these fruits to start ripening, further south they may start ripening in June. Late picking varieties can extend the season.
One year, as usual, the Methley plum harvest was generous. One weekend I was exploring ways to make use of the fruit other than steaming to make juice. I wanted the pulp, and maybe some of the skin, to make jam, fruit leather, or sauce. However, the pits are cling stone, so are challenging to remove from the pulp. In the past I cooked the fruit, and then sifted the seeds out by hand, a long and tedious job. This year I put the washed fruit in my blender, with the plastic blade, processed just long enough to break the pulp down, maybe 15-30 seconds, and poured the puree into my jelly cone. After working the pulp about 30 seconds with the plunger most of the puree had gone through the cone, but the pits were interfering with removing the last of it. I grabbed a rubber scraper, worked the mash around a bit, and the last of the puree went through the cone, leaving behind the pits (nicely cleaned of pulp) and most of the skins. The skins are pretty tart on the Methley, so that was OK. One hour of processing yielded about 7-8 quarts of pulp. The straight pulp can be used for jam (use your favorite pectin and follow label directions) or sauce. Heat the pulp to a slow simmer, stirring regularly to prevent sticking and burning, until the puree is of a sauce consistency. Add applesauce (about 1/3 part applesauce to 2/3 parts pulp) to make fruit leather or butter.
This technique would be useful for any of the very juicy asian plums, which are all cling stone.
There is more recipe information on our website, use the Raintree Recipes link found in the Growing Info page, link in the top tool bar.
Spider mites thrive in the hot, dry weather of August. Inspect potted citrus, growing inside or outside, for spider mite infestation. Look for a yellow stippling pattern on the top side of the leaf, the under side will have light webbing and you may be able to see the small spider like insects moving about in the webbing. Willows, akebia, roses and himalayan honeysuckle are all favored hosts. Control with insecticidal soap spray, applied every 3 days, for a total of three sprays. Then spray once a week until the hot dry weather is done for the year. You may add a light weight oil, such as canola or neem oil, to improve the effectiveness of your spray. Use 1-2 Tbsp of oil per gallon of spray solution, or follow the label if you choose an ultra-light summer weight oil. If you add oil, do not spray when temperatures the plant will experience will exceed 90° F for three days following application or you may see leaf damage. Always test a new mixture on a few leaves first, to make sure you won’t damage leaves. Some plants are very sensitive to oils. Our Raintree Plant Owners Manual has more information on controlling insects on your potted plants, see page 22.
Fertilize container plants as needed to maintain adequate fertility for healthy growth. Summer watering can flush nutrients out of the soil mix. Slow release fertilizers may not be contributing much nutrient any more. Use a liquid fertilizer to finish out the growing season, or another light application of slow release. A formulation with less N (nitrogen) and more P (phosphorous) amd K (potassium) will help plants finish ripening fruit and prepare for winter with more sturdy growth.
If your day time temperatures are regularly above the mid-80’s now is not a good time for planting, even if the plants are potted (unless you pay special attention to water and shade for the plants after planting), but soil preparation of planned planting sites for fall or next winter can be done. Clear away unwanted perennial vegetation, turn the soil once (if it’s moist enough to dig) or loosen with a digging fork, and cover the area with coarse compost or mulch. A typical area size would be a 2-3’diameter circle for a 1-4’ shrub, 3-5’ diameter circle for a potted or bare-root tree. At planting time rake the mulch away, dig the hole and plant according to instructions in the Raintree Owners Manual. After watering in your new plant replace the mulch, add additional material if necessary to make a 2-4” blanket on the surface. Remember to always keep the mulch 3-6” away from the trunk.
Late summer is the time to do your summer budding. Stone fruits, such as apricots, peaches, cherries, and nectarines, and certain cultivars of other fruits propagate most reliably from summer budding. Budding is also an excellent technique for making the largest number of trees from a limited quantity of scion wood.
Budding is done by removing a bud from the desired variety of tree and inserting it in an established rootstock. The rootstock can be a new rootstock planted lasat spring for this purpose, or an existing fruit tree you would like to add a new variety to. For summer budding, the bud stick from the desired variety is collected near to the time you will be doing the grafting. Select a vigorous vegetative shoot (i.e. water sprout shoot with pointed vegetative buds) that is ¼-3/8” in diameter from the current year’s growth. In the later part of summer the buds in the lower part of the shoot will be mature and dormant, and the stem will be firm and tend to break if you bend it. The buds near the tip of the shoot will still be actively growing, and the stem will bend without breaking. Harvest the shoot (bud stick), and immediately remove the leaf blades, leaving about ½” of petiole attached to the shoot. Discard the immature tip of the shoot and the basal whorl of buds (which may be flower, rather than vegetative, buds). The rest can be cut into convenient 6-10”lengths. Label, wrap the bud sticks in barely moist paper towel, and seal them in a bag to retain freshness. You can store the prepared bud sticks at 35-40°F, up to a couple weeks, but using them right away is best.
Here in the Pacific Northwest late August to early September is usually the best time to bud graft. The grafts will heal best if day time temperatures are in the mid-60’s to mid-70’s, and night time temperatures above 50° F, for 10-14 days following the grafts. It is also necessary that the rootstock is actively growing when you do the bud graft for the graft to heal properly. When a tree is actively growing the cambium layer underneath the bark is actively growing, and has a lot of moisture in it, so it easily separates from the bark. This is called slipping. To determine if the rootstock is in good condition for grafting make a test cut in the bark, higher than where you intend to put the bud. Make a vertical cut, then a horizontal cut at the top, to make a T. Try to open the flaps of the T. If they open easily the bark is ‘slipping’, if not, now is not a good time to graft. To encourage a rootstock to be actively growing when you want to do your grafting, keep it watered, and fertilize a couple weeks before you intend to graft.
T-buds and chip buds are the two most common bud grafts. Commercially chip buds are preferred, they are quicker to insert. T-buds tend to be more successful for those with less experience. There are many resources that describe and provide pictures of doing the grafts. Raintree Nursery offers the following, Budding and Grafting (#S050) and Plant Propagation (#S080). Tools you will need include: a grafting knife (with single beveled edge), budding strips or chip bud tape, alcohol (to keep your knife clean), and labels. Go to our grafting supplies page for descriptions. If the ground is damp we might have a piece of cardboard to sit on, or wear knee pads if a person prefers to kneel.
What do I do if a plant is not growing vigorously the first year the way I expected it too? First we have to determine why. Sometimes it is in the nature of the plant not to grow vigorously in the first year, such as Monkey Puzzle or Bamboo. More often the root system is not growing and establishing properly. There can be several reasons why:
Perhaps the top of the tree started growing before the roots after the tree was planted (this often occurs when daytime temperatures are warm and the soil is still wet and cold after planting), creating an imbalance in the tree. The demands by the top of the tree for water and nutrients are using up all of the energy resources in the tree, so the roots aren’t growing. Re-establish balance in the plant by providing 50% shade from the mid-day sun, and keep the soil evenly moist (not constantly saturated).
Over watering a newly planted tree will keep the soil wet and cold. Check the soil 4-6” deep for moisture content before watering, where the roots are, rather than looking at the surface. In addition, if the ground remains constantly wet oxygen is pushed out of the soil, which the roots also need for active growth.
Too much modification of the soil in the planting hole can also lead to problems for the root system. Sometimes water does not exit the planting hole as fast as we thought it would, keeping the soil wet and cold, because the soil porosity created in the planting hole is too different from the native soil. Maybe the roots are not eager to leave the planting hole because what is in the planting hole is too nice compared to the native soil. Over-fertilization with chemical fertilizers or animal manures in the planting hole can burn the roots, stopping them from growing until the excess nutrients have leached out of the soil.
The best solution when preparing the planting hole? Keep the fertilizer to a minimum, do not add more than 20% compost to a planting hole (about 2 shovels full), and fracture the sides of the hole before planting. After planting fracture the ground next to the planting hole (I use a digging fork), mulch with straw or leaves, and water only as necessary the first few weeks. Finally, order your plants now through the first of the year so we can deliver them to you at the beginning of your planting season.
If the roots are not growing vigorously the top of the plant will not grow vigorously.
It is perhaps on the most sweltering days of summer that the cooling shade of trees is most appreciated- or missed. If your thoughts are turning to what to plant for future summer shade, here are a few ideas. On larger properties where space is ample, don’t overlook the potential for Big Leaf Maple, (Acer macrophyllum) (#M315), a Pacific Northwest native, to develop into classic shade tree dimensions. Where space is more limited, Vine Maple (Acer circinatum) (#M300), another Pacific Northwest native, can be trained to a single trunk for a moderate sized shade tree. Vine Maple is our primary native source of fall red and orange color. Are you in a hurry to get your shade? The Empress Tree (#M580) is one of the fastest growing shade trees available to growers in mild winter areas, growing quickly to 20’, then more slowly up to 40’ tall. Tree serviceberries, maples, black locust (particularly Frisia), birch, and nut trees are all beautiful shade trees, and some produce food for you as well. Take a good look at your property, and choose a shade tree that will not overgrow your space. Locate your tree where leaves and other falling debris will not be a nuisance in your gutter, or on your sidewalk. You can also create shade by putting up a sturdy structure and training a vine over it, such as grapes, kiwi, akebia, or honeysuckle - a useful technique where root zone space is limited.