How to Grow and Care for Hawthorn Trees

A hawthorn tree is in the genus Crataegus and it is a pleasing ornamental small tree and shrub the perfect size for smaller settings. The tree has sweet little five-petal blossoms that arrive in the spring. This tree is sturdy and easy to grow.

With all of its positive attributes, the tree may have one major disadvantage to growing it in your yard. Some, but not all, hawthorn trees have intimidating thorns that can grow up to 3 inches long. Some other types of hawthorn trees have been bred to be resistant to growing thorns as well as disease- and insect-resistant, which allows gardeners to enjoy the beauty of this genus.

Planting a Hawthorn Tree

When to Plant

Plant a hawthorn tree in the early spring or early fall. Choose a mild time of year so the tree is not stressed when planted in the ground.

Selecting a Placement Site

Choose a site that is in full sun for better blooms, but the tree will also do well in partial shade. Though the tree prefers well-drained soil, the hawthorn will tolerate poor soil, as well as pollution conditions. Since the tree is smaller than many landscape trees, it is okay to plant it near a structure, such as a house.

Spacing, Depth, and Support

Plant a row of trees at least 20 to 30 feet apart for adequate room to grow. They can grow up to 35 feet wide. Plant a root ball in a hole that is two or three as wide and deep as the root ball. Stake young trees to protect them from the wind.

Hawthorn Tree Care

Often the species of the genus find themself susceptible to issues such as disease or insects. While integrated pest management does help, the genus' issues have been addressed through selective cultivation and grafting. Today in ornamental horticulture, the most popular hawthorns are grafted or cultivars.

There are three elements to being successful when growing a hawthorn. You will need to accept that they are susceptible to some issues and realize that you will have to take some steps to deal with those issues.

Normally it is a great idea to go native, and it still is, but in doing so, you will need to be extra vigilant in your integrated pest management program. This is a great example of a tree where it is worth bringing in a certified arborist to do some yearly tree care.

Plan to do some research and find out what insects and diseases are in your area and if they will affect the species or variety you have chosen. You can find this information from the Plant Sentinel Network or your local extension service.

Light

This flowering genus will do best in a location that receives full sun. Placing the tree in a location with anything less will produce a noticeable drop in blossoms.

Soil

Surprisingly, as susceptible as the genus is, it will tolerate any soil type and pH level as long as the soil is well-draining. Its ideal soil is slightly moist, slightly acidic, and well-draining, but the soil is not the biggest priority when dealing with hawthorns.

Water

Establishing your hawthorn will require you to provide it with plenty of moisture for the first two years or so. To do this, it's best to water it weekly. Figure out just how much to water your tree by measuring its diameter at your knee height with a set of calipers. Then give it 10 gallons per inch every week for the next two seasons, remeasuring every so often.

Temperature and Humidity

The hardiness will vary on the species or cultivar and may differ greatly as the genus is dispersed over many continents. Research the viability of a certain species or cultivar in your hardiness zone before deciding to plant.

Fertilizer

Giving hawthorns an application of fertilizer in the fall should be on your to-do list every year. Being a flowering tree, it will benefit from the added boost of nutrients you provide it. Apply a granular slow-release fertilizer formulated for flowering trees and shrubs, and your hawthorn will be bursting with blooms. For the amount to use, follow product label instructions.

Types of Hawthorn Tree

If you go the non-native route, pick a disease- and pest-resistant variety of hawthorn. There are many selections of Cratageus available that are resistant to fire blight and rust which are equally beautiful. You will need to find the right tree for your zone; the choices are endless. Here are a few popular choices:

• Canadian, C. canadensis: A frost-hardy hawthorn that grows to about 30 feet. It can withstand city pollution.
• Washington hawthorn, C. phaenopyrum: A small hawthorn with extremely bright berries and striking fall color.
• Cockspur hawthorn, C. crus-galli: Low-growing, wide-branched, and thicket-like hawthorn with branches that touch the ground. It produces an assortment of colors in the fall.
• Copenhagen hawthorn, C. intricata: A small shrub-like hawthorn, hence the specific name, that grows only to about 10 feet. It is known for its value as a habitat for wildlife and as a food source for pollinators.
• English hawthorn, C. laevigata: A popular street tree with white, pink, or red flowers, English hawthorn grows in difficult environments other trees can't tolerate.
  

Pruning

First, pruning a hawthorn tree is a job that needs to be done carefully and properly protected with leather gloves, eye protection, and a helmet. The thorns on a hawthorn are very long and hard.

Hawthorn trees may develop thicket-like habits if they are not trained to have a single leader and outward branches. To train your tree, you will want to establish a single leader and cut off any low-hanging branches that create a sharp V-shaped crotch or X-shaped intersection with another branch. This should be done annually in the fall after the tree has dropped its leaves. You should continue training your hawthorn in this way until it is shaped into the desired form. When it is too large to prune from the ground, it's best to call a licensed arborist as this can be a dangerous tree to prune.

Common Pests and Plant Diseases

Pests that bother hawthorn plants include aphids, scale, cankerworms, lacebugs, leafminers, and spider mites. Insecticidal soaps can be of great help in reducing pest problems.

Hawthorns most often suffer from hawthorn rust and fire blight. Hawthorn rust is a tree disease caused by the fungus Gymnosporangium globosum. This disease rarely kills trees but will always disfigure them, and worst of all, if a tree is infected, it can either only be managed or taken down and not cured. This is why it is important to consider choosing rust-resistant hawthorns.

Fire blight is a bacterial disease that affects hawthorns. The disease kills blossoms, and shoots, and causes the dieback of branches. In severe cases, it can cause the trees to die.

How to Get a Hawthorn Tree to Bloom

The hawthorn tree's fragrant, delicate white or pink flowers look just like apple blossoms. To ensure you get profuse blooms in the spring, you will want to keep your tree's soil moist but not soaked. If rainfall doesn't provide this requirement, then you may need to water regularly. Adding a layer of mulch around the tree's base at a depth of 2 inches out to the dripline without touching the trunk will help it retain moisture. Since the tree adapts to most soils, the soil condition it's growing in will not have any obvious effect on the plant's health or bloom production.

Common Problems With Hawthorn Tree

The hawthorn tree typically does not cause many issues. But be on the lookout for the following signs of trouble.

Yellow and Dropping Leaves

The tree may have leaf spot. Control this issue with fungicide spray. Always remove fallen leaves from the base of the tree in the spring and fall to lessen the spread of fungal infections.

Orange Spots on Leaves

The tree could have other fungal problems, such as leaf or stem rust. Long and rainy spring seasons can cause these issues. Rust is caused by excessive moisture on trees and in the soil around trees. To alleviate this issue, avoid excessive watering and prune your tree to allow good airflow. Use fungicides to control the problem.

Black-Brown Leaves

If the leaves of the tree turn blackish-brown and shrivel up, it may have fire blight, a bacterial disease. To control blight, prune your hawthorn to remove infected branches before the disease kills the tree. You can prevent blight by planting resistant varieties.