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Willow Trees

Weeping willow foliage over a pond.
weeping willow image by Edsweb from Fotolia.com

How to Fertilize Weeping Willows

Weeping willow trees, known botanically as Salix babylonica, are deciduous ornamental trees grown primarily for their dramatic foliage canopies. Weeping willows thrive in moist nutrient-rich soil often near bodies of water. The trees are rapid growers and their root system is large so the trees can benefit from light fertilization each year with feeding becoming more important when the tree is growing in nutritionally deficient soil.

Feed your weeping willow once each year in the spring after the last frost has passed and the soil is warm and can easily be worked and absorb the applied fertilizer and water.

Apply a complete and balanced organic or slow-release fertilizer formula that is rich in nitrogen with a guaranteed analysis of 10-10-10 or 20-20-20. Follow the dosing directions on the product label using the recommended amount for the size and age of your tree, never applying more than the recommended dose.

Spread the fertilizer over the soil under the tree. Start at least a foot out from the trunk and extend the spread to the outer branch tips of the drip line of the tree. Nestle the fertilizer into the top 2 inches of soil with a rake or hoe, distributing it evenly.

Water the fertilizer and surrounding soil in deeply to begin to wash the nutrients down into the soil and the root zone. Drench the soil to a depth of at least 8 to 10 inches to ensure good distribution and prevent drought stress.

Weeping Willow Infested With Worms

Identification

An adult carpenter worm appears as mottled black and gray moth that can measure up to 3 inches in width. The hind wings of the female moth are white and the male's hind wings are orange. The light green worm-like larvae of the moth measure up to 3 inches in length and 1/2 inch in diameter.

Damage

In spring, the female lays up to 200 eggs in the willow tree's bark crevices. When the larvae hatch, they burrow into the wood. The worm-like larvae will reach the heartwood within four months of burrowing, according to Utah State University.

Control

Dead areas of bark will result and may fall from the tree. The insects weaken the willow tree and make it susceptible to wind damage. Injectable insecticides can help control the larvae. Spraying the tree with insecticides before the larvae enter the bark will also help control the pests.

How to Graft Weeping Willow Trees

Make a 1 1/2 inch cut on the main trunk of the root cut starting from the outside of the root upward to create an angled cut with a sharp edge at the top.

Make a cut straight down through the middle of the trunk beginning halfway down the initial cut and ending at the base of the first cut. Cut, don't split, this second cut.

Make a matching cut on the scion, including the center tongue cut.

Slip the scion into the root stock, mating the tongue cuts for optimal contact between the scion and the root stock.

Wrap the graft tightly with grafting tape to help maintain contact.

Cover the graft and tape with grafting compound to seal the graft.

Remove the grafting tape and compound once the grafted portion of the tree has started to grow.

Information on Weeping Willows

History

Although a native of China, the weeping willow is now widely grown in North America and other countries. Weeping willow bark was used medicinally by Native Americans to treat headaches. The bark contains salicylic acid, an ingredient later used to make aspirin.

Identification

The weeping willow has a short, stout trunk and long, pendulous branches with narrow, green leaves. Its small, yellow flowers bloom in April or May and are not showy.

Considerations

The weeping willow enjoys full sun to partial shade, and thrives in a variety of soils. It is a fast-growing tree that is propagated in spring by rooting the cuttings of softwood in deep soil.

Maintenance

Gardeners prune overly-long branches in late winter or early spring before the buds open. Regular removal of crowded branches will maintain a freely-weeping appearance.

Warnings

The invasive roots of the weeping willow travel a great distance from the trunk and can damage sewer or water lines and septic tanks. The tree is susceptible to some pests and diseases, including aphids, tent caterpillars, powdery mildew, crown gall and canker.

Famous Ties

Claude Monet painted a series of weeping willow tree scenes to honor the fallen French soldiers of World War I.

Problems With Willow Tree Roots and House Foundation

The weeping willow needs lots of space.
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Growth Pattern

The weeping willow grows quickly, often becoming too large for its designated space. Its roots grow aggressively, seeking out water below ground. Drought conditions tend to worsen this situation, as water close to the surface becomes scarce. The willow's roots search for leaks in a foundation, or water, sewer and septic system. For these reasons, the University of Tennessee Extension includes the weeping willow on its list of trees to reconsider before planting.

Foundation Damage

Willows look for wet areas, especially leaking pipes, foundations and septic drain fields. Though the roots normally do not grow under foundations, if moisture is present, they will be drawn into the cracks. As the roots increase in diameter over the years, structural damage can occur. Damage to a shallow foundation is more likely than damage to a deeper foundation.

Solutions

Moisture prevention is key to protecting against damage from weeping willow roots. Eliminate moisture problems around and under foundations. Replace leaking pipes. Use rain gutters to divert any water flow away from the foundation. If the roots are threatening the foundation, excavate around the house and cut the roots, then install a root barrier. As a last resort, have the tree removed. If a drooping form is desired in a residential landscape, the University of Tennessee Extension recommends the weeping cherry, mulberry or birch instead.

How Long for a Weeping Willow to Grow to its Mature Size?

A weeping willow is a fast growing tree, which means that it grows at 25 inches or more a year. The weeping willow is fully grown and mature at 30 to 40 feet tall. Therefore, it takes about 14 to 19 years for the weeping willow to reach its mature size.

How to Trim Weeping Willow Trees

Trim weeping willow trees in late spring to early summer to reduce the amount of sap produced by the pruning cuts. Use hand pruners to cut limbs up to ½ inch in diameter and lopping shears to cut larger limbs. Cut limbs at a 30-degree angle at a bud, or a joint.

Shorten limbs that touch the ground or interfere with walkways or driveways, using hand pruners or lopping shears.

Remove limbs that cross or rub each other, or that are damaged, diseased or dead. Cracks in the bark, oozing lesions, cankers, and dying foliage are symptoms of diseased limbs.

Prune limbs that are growing upward on grafted trees. Do not prune upward growth on trees that are not grafted.

Pinch or rub off lateral growth on the trunk. Use hand pruners to remove suckers from the base of the trunk.

How to Prune a Japanese Willow Tree

Remove any dead, diseased or damaged branches from the Japanese willow as they occur. Cut them off at the base of the shrub.

Remove 1/3 of the branches on the Japanese willow in the late winter or early spring. Remove the interior branches that are not flowering or producing foliage. Cut the branches down to the ground when you prune.

Trim off, or deadhead, the blooms as they fade to promote new flower growth.

How to Kill Willow Tree Aphids

Boil 4 pints of water in a large cooking pot on the stove.

Grate four lemons using a food grater to gather all the zest from the peels. Dump the zest into the boiling water.

Remove the pot from the heat and allow the mixture to cool completely. Strain into a tree sprayer.

Spray the leaves and foliage of the willow tree thoroughly. Also spray any existing clouds of aphids that are lingering nearby.

How to Prune Willow Bushes

Prune wilted branches as needed throughout the year. Willow bushes are hardy and don't need much ongoing maintenance, but wilted branches suck excess nutrients from healthy stalks. The rest of the plant perks up once you cut the wilted parts.

Cut back old growth in spring. Removing old stalks is called "hard cutting," and it helps the plant produce new, vibrant stalks during the growing season. Trim stalks more than one year old close to the ground, leaving only the freshest, greenest branches intact. If you're happy with the willow bush's current size, you don't need to cut off old growth.

Trim away winter-damaged stalks during springtime. Hard cutting is optional, but springtime maintenance helps keep the plant healthy. Branches snapped or strained from snowfall are a burden to your willow, and you need to excise these branches.

How to Cut & Plant Hybrid Willows

Cut a twig from the hybrid willow tree. It should be at least 10 inches long, cut from a dormant branch.

Dig a hole in the soil and bury the cutting, with the buds pointing up, as deeply as possible. The cutting will form roots along the entire length that is buried under the soil.

Water the cutting well and keep the soil moist, not soggy. Your hybrid willow cutting should root within one month.

When Is the Best Time to Prune a Willow Tree?

Proper pruning can enhance the health and appearance of your willow tree.
Thomas Northcut/Photodisc/Getty Images

Shaping

The best time to perform heavy pruning on your willow tree is after it loses its leaves in the late fall or winter. The bare branches allow a clear view of the tree's form, enabling you to cut the overgrowth away quickly and easily. Avoid heavy pruning for shaping purposes during the summer months, when the presence of disease pathogens increases the risk of damage.

Removing Damage

The best time to prune off damaged or diseased branches is as soon as they appear, regardless of the season. Disinfect your pruning shears with a solution of 1 part household bleach to 9 parts water, dipping the shears after each cut. Remove damaged growth about 2 inches above the affected portions.

Cuttings

Many types of willows propagate readily from vegetative cuttings. The best time to prune sections for propagation purposes is in the spring. Select just a few branches from each willow tree, removing just the top 10 to 15 inches of pliable branches containing numerous leaf buds. Inserted in a solution of water and rooting compound, these branches often form new roots.

How to Germinate Desert Willow Seeds

Fill a plastic bag with wet sand. Bury the seeds inside the sand and seal the bag. Leave the seeds in the bag for two to three days to help speed germination.

Fill 6- to 8-inch pots with potting soil. Sow the seeds to a depth twice that of their width and moisten the soil thoroughly.

Set the pots in a warm 65 to 75 F room to germinate. Germination takes seven to 14 days. Keep the soil moist but not soggy during this period.

Salix Caprea Pendula Care

Willow flowers are called catkins.
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Hardiness

Salix caprea 'Pendula' trees can tolerate temperatures down to minus 30 degrees Fahrenheit. They do well in USDA hardiness zones 4 to 8.

Selection

Salix caprea 'Pendula' trees are often sold grafted onto other types of root stock so they grow a single trunk upright, then weep like an umbrella. Ungrafted willows creep along the surface as a ground cover. To maintain tree form, they need to have their trunk supported upright and trimmed of all side branches until they are over 6 feet tall.

Planting

Salix caprea 'Pendula' grows well alongside water such as near a pond or small stream. They need wet to moist soil in full sun to light shade.

Liabilities

Salix caprea 'Pendula' can be difficult to care for and is prone to insect attack and blights that may require chemical treatment to control. The sucker branches need to be pruned off regularly to maintain the tree form, and the leaf litter under the tree must be frequently cleaned up.

Can You Root a Dappled Willow Shrub?

Like many willows, dappled willows have yellow spring catkins.
willow image by Pali A from Fotolia.com

Dappled willow (Salix integra 'Hakuro-nishiki') is an attractive Japanese shrub with pink spring foliage that changes to variegated green and white. Root new trees by placing 8-inch stem cuttings in a pot of well-drained, consistently moist soil. Wait until roots show in the container's drainage holes before planting them.

How to Plant Willow Trees

Plant willow trees as soon as possible after purchasing and make sure it is at least six weeks before the first frost. If the roots appear to be dry, sprinkle them with some water. If you cannot plant the tree immediately, store it in a dry, cool, dark place like a basement.

Make the planting hole twice as wide and deep as the willow's root ball. This gives the roots the room they need to spread out. Use the tree as a judge to determine size as you dig.

Place the tree centered in the hole. Make sure it is sitting straight up and down. Refill the hole with the removed soil, packing it in around the roots.

Press the soil down to remove air pockets. The air will dry out roots if they are allowed to remain.

Water the weeping willow thoroughly after planting. During the first year of growth, water the tree only during extended dry spells.

Where to Find a Diamond Willow Tree

The Copper River in Alaska, is the most famous location for diamond willows. Varieties are found throughout the forested areas of Alaska from the Kenai Peninsula north. This tree is not exclusive to Alaska, but it grows only in the northern portion of North America. Diamond willow is nearly as rot-resistant as cedar.

Rate of Growth for a Willow Acacia

Size

The willow acacia tree can reach up to 40 feet in height and have a canopy about half the width of the height. The tree grows roughly at the rate of 25 inches per year, according to the Urban Forestry Program in Tucson, Arizona.

Features

The willow acacia grows quickly and has thin branches that arch up and hang down like a willow. The leaves are small and can range in color from gray to green or blue-green. According to the University of Arizona Cooperative, the tree is a smooth-barked tree until it matures and develops fissures.

Between late summer and early winter, the tree produces tiny clusters of puff balls that are creamy white to yellow flowers.

Considerations

The willow acacia grows best when planted in full sun and in soil that drains well. The tree can be planted in numerous types of soil and is drought tolerant according to Florabank.

Geography

Originating in Australia, the willow acacia can now be found in many regions throughout the world. The plant can tolerate cold temperatures as low as 20 degrees Fahrenheit.

Maintenance

To keep the canopy of the willow acacia thinned, the tree can be pruned occasionally. The tree is basically self-sufficient and requires little maintenance over the years unless it is struck by disease.