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Lilacs

Japanese lilac trees fill the garden with fragrance.

How to Prune a Japanese Lilac Tree

Japanese lilac (Syringa reticulata) is a large shrub or small tree that blooms with fragrant white flowers. Japanese lilac trees are the perfect solution for a small garden space because they grow 15 to 20 feet in height with a 15-foot spread. Unless your Japanese lilac is overgrown, it won't require heavy pruning. Japanese lilac branches don't bloom until they are three years of age, so use caution when cutting old wood. Prune the Japanese lilac tree immediately after flowering.

Trim large stems from the center of the Japanese lilac tree by cutting them back to a main branch or the trunk. This will open up the tree for better ventilation.

Remove suckers from the soil around the tree or from the trunk near the soil. Use pruning shears to clip them off completely.

Prune the tree to the shape desired. Prune from the sides to create a slimmer profile, and trim from the top of the tree to remove height. When you cut back a branch, cut it to 1/4 inch above a bud (swollen part of the stem or branch).

How to Prune Lilac Bushes in the Fall

Cut away any spent blooms on the ends of the branches. Clip the branch with hand pruners just behind the blooms and just after a set of leaves.

Look over the lilac bush for old, brittle branches, branches that rub against one another, and any misshapen branches. Use lopping pruners to cut away these branches as close to the ground as possible. Clip old branches only every three to five years.

Step back from the lilac and review overall shape of the lilac bush. It should be a wide “V” shape. Cut away any branches from their base that disrupt this shape or are rubbing along the side of a wall or fence. Leave behind at least five strong stalks.

How Big Are Japanese Lilac Dwarf Trees?

Japanese lilac trees produce showy purple blossoms in the spring.

Japanese lilac trees (Syringa reticulata) can grow to be up to 25 feet tall. There are no dwarf varieties of this tree. However, the Korean dwarf lilac, the most popular variety of which is "Miss Kim," grows to be around 5 to 8 feet tall.

Do Lilac Trees Need to Be Protected From Frost?

Lilac tree

Lilac trees need to be protected from frost. Some varieties, like Syringa patula ‘Miss Kim’, are more frost hardy than others. Protect lilac trees from frost by covering them with a lightweight bed sheet or cloth tarp.

How Fast Does a Dwarf Lilac Tree Grow?

Lilacs are fast-growing trees.

There are several varieties of dwarf lilic trees, including the Persian lilac and dwarf Korean lilac. Depending on the variety, they may grow as tall as 4 to 8 feet in height. The trees are fast growing, adding 1 to 2 feet to their height each year.

Care for a Korean Lilac Bush

Plant your Korean lilac in a spot where it will receive four to six hours of sun each day.

Remove or prune any vegetation within a 10-foot radius of the Korean lilac. This bush requires air circulation in order to help it ward off disease.

Water the Korean lilac when the top 2 inches of soil are dry. Poke your finger into the soil to ascertain when it is time to water.

Prune the Korean lilac no later than the last week in June to keep it the size that you want.

Fertilize the Korean lilac immediately after pruning. Use an all-purpose fertilizer at the rate suggested on the label. Apply the fertilizer in a ring, 1 foot away from the base of the bush.

Pinch off fading flowers during the growing season and dispose of them.

How Big Does a Japanese Lilac Tree Grow?

Like shrub lilacs, Japanese tree lilac has fragrant blooms.

The Japanese lilac tree (Syringa reticulata) is an ornamental tree standing from 20- to 30-feet high. Flowering in spring or early summer, it has upright clusters of eye-catching, fragrant white blooms. Japanese lilac trees tolerate winter temperatures as low as minus 40 degrees Fahrenheit (USDA Plant Hardiness Zone 3).

How Can I Plant a Shoot of a Lilac Tree Successfully?

Cut new growth shoots from the lilac tree that are 4 to 8 inches in length. These shoots are growth that continues after the lilac tree has bloomed.

Dip the cut end of the shoot into water and then immediately into rooting hormone. The lower inch of the cutting should be covered with the rooting hormone powder.

Fill 6-inch growing pots with sand. Water the sand until water drains from the bottom of the pot.

Use a pencil or chopstick to create a hole 2 to 3 inches deep in the sand.

Place the lilac shoot into the hole and press the moist sand around the cutting to keep it upright in the pot.

Keep the sand and the cutting moist to the touch at all times. Lilacs prefer high humidity so moisture for the cutting is imperative.

How to Stake a Dwarf Korean Lilac Bush

Measure the length of your lilac trunk from the soil line to just under the canopy. Add at least 6 inches to that measurement for the portion of the stake that goes into the soil. Acquire or cut a sturdy timber or metal stake to the desired length.

Slide the stake alongside the trunk so that they nearly touch and run parallel to one another. Drive the stake into the soil until secure and standing upright, at least 6 inches.

Tie the lilac trunk to the stake at the top just under the canopy line, at the middle and roughly 1 foot above the soil. Use soft, flexible garden tines that will not dig into the lilac bark or girdle the trunk over time.