Hawthorn tree (Crataegus) is a reliable and stately addition to most spaces. A deciduous ornamental plant, it’s glossy foliage and white flowers provide interest from early spring through the height of summer and into fall.
The hawthorn tree is also known as May blossom, or May flowers. The rhyme “here we go gathering knots of May”, refers to the old practice of picking the flowers of the hawthorn tree.
Stately and attractive, the May flower is a popular addition to urban gardens.
Ideal for urban gardens, while one plant makes an elegant ornamental feature, a row of hawthorn is a great natural hedging option. The plants can also be used as part of a forest garden planting scheme. Easy to maintain, hawthorn hedges are also popular with wildlife such as garden birds and pollinators.
A pleasingly hardy plant, if planted in a favorable position the hawthorn tree can live for up to 400 years. If you want to add a hawthorn tree to your garden, this guide will take you through everything you need to know.
Different Hawthorn Tree Varieties
There are a number of different cultivars available. Specialist plant nurseries often have a wider range available than your local garden store. They may also be best placed to answer specific questions about growing in your local climate.
The most commonly grown variety is the common hawthorn tree or Crataegus monogyna. This variety produces large amounts of cream flowers which are replaced by dark red berries in the fall. Common hawthorn, when mature, has a height and spread of between 13 to 26 ft.
An individual common hawthorn tree makes an excellent ornamental feature. If you want to introduce privacy to your garden, try planting a few common hawthorns together. This creates a robust hedge.
Reaching 20 to 30 ft in height Cockspur hawthorn, Crataegus crusgalli, is another popular choice. Best known for its long thorns, that can reach up to 3 inches in length, this cultivar is ideal for hedging.
The cultivar of Crataegus laevigata known as Paul’s Scarlet, is a compact plant which is suitable for smaller spaces. Unlike the common hawthorn tree, this plant produces showy red double flowers. Another C. laevigata cultivar is Rosea Flore Pleno. It is grown primarily for its attractive pink, double flowers. A similar variety, Crimson Cloud, produces finely textured foliage and bright red flowers.
While May flowers are typical white, some cultivars produce attractive pink or red blooms.
Crataegus persimilis Prunifolia is a broad but small plant. When fully mature it can achieve a spread of over 26 ft. Prunifolia produces the typical white flowers and red berries of the hawthorn tree, but in the fall the plant’s foliage turns attractive shades of orange and red. Washington hawthorn (C. phaenopyrum) is one of the most disease resistant cultivars. Producing brilliant white flowers, the foliage of the plant naturally changes from shades of green to red and orange hues as the year progresses.
Finally, some cultivars such as Inermis are thornless.
Where to Grow
May flowers are best suited to USDA Zones 5 to 9.
Plant in a sunny position. Full sun positions are preferred. May flowers can also grow in partial sun but growth may be slower.
The soil should be well draining. Before planting work the soil over well. Amend heavier soils by working in rich homemade compost, organic matter or horticultural sand. As long as the soil is well draining, the plants tolerate most pH levels.
If you want to plant in the middle of a lawn begin by removing a circle of turf roughly 2 ft in diameter. The tree will sit in the center of this circle. Weed the exposed soil thoroughly and work in organic matter before planting.
How to Plant
Hawthorn plants can be sold as either bare root trees, or as potted plants.
You can plant bare root trees at any time from November until March.
May flowers sold in pots can be planted at any time of year, but most people avoid planting during the summer months. This is because the hot, dry summer days can make it difficult for plants to establish themselves before winter comes. Planting in spring gives your plant plenty of time to become accustomed to its new home.
Weed and amend your soil before planting. Properly preparing the soil helps plants to quickly settle into their new home.
Use a shovel to dig a hole roughly 2 ft wide and 12 inches deep. If you are planting a potted sapling the hole should be large enough to hold the pot.
Dig a layer of organic matter into the bottom of the hole. Well-rotted manure is ideal, as is homemade compost.
Position the plant in the hole, allowing the roots room to spread. Plant to roughly the same depth as when the plant was in its container. If you are unsure, aim to plant so that the top of the root system is level with the soil.
When you are happy with the position, backfill the hole with an even mixture of soil and organic matter.
Stake the tree to provide support in windy conditions. I find that the Kradl Tree Staking Kit provides an unintrusive way to support growing plants. It is also easy to use and is pleasingly resilient.
Water the base as well as the area around the tree well. Spread a granular feed over the moist soil. Finally apply a 2 to 3 inch thick layer of mulch such as bark chippings or compost around the root area.
The best time to transplant is in spring, at the start of the growing season.
Preparation is key to successful transplanting. Healthy shrubs are more likely to survive transplanting than unhealthy plants.
The summer prior to transplanting, start fertilizing your shrubs. Watering correctly and pruning away any dead or damaged wood also helps to bolster plants.
In the fall, root prune the shrubs to encourage a compact root system to form. To root prune, draw a wide circle around each shrub. This circle should include a large amount of the root system. Dig straight down with a sharp shovel, working your way around the perimeter of the circle. This severs the shrubs’ longer roots.
In the spring prepare your new site for planting. The day before transplanting, soak the soil around the shrubs well. Tying the branches closely into the plant helps you to get up close without getting attacked by thorns.
Re-dig the perimeter circle, digging down far enough that your shovel is below the root ball. Once you have encircled the shrub a few times, you will be able to lift it from the ground. Place on a sheet of tarp and cover the roots. Re-plant as described above, as quickly as possible.
How to Care for a Hawthorn Tree
Once established, hawthorn tree is a pleasingly low maintenance plant.
When plants are young and growing, keep the soil around them as weed free as possible. Weeds quickly harvest moisture and nutrients from the soil. This can leave plants struggling to get the sustenance they need.
When to Water
During the first year, aim to keep the soil evenly moist. Water the soil around the plant during any dry spells. Don’t allow the area to dry out. An expandable hose makes watering large areas a simple task.
Once established, these plants are pleasingly drought resistant. However, they will appreciate a little water during prolonged dry spells.
Applying a 2 to 4 inch layer of organic mulch helps the soil to retain moisture as well as suppressing weed growth. Keep the mulch at least 6 inches from the base of the trunk.
Wood chips are a great long lasting, organic much choice.
Fertilizing May Flowers
For the first three years after planting, fertilize once a year with a balanced fertilizer.
From year four onwards, fertilize once every other year with the same balanced fertilizer.
The best time to fertilize is in the spring before new growth emerges.
Liquid fertilizers can be incorporated into watering routines. Granular plant foods, such as Epsoma Garden Food, are also easy to apply. The exact amount you need to apply varies depending on the fertilizer you are using and the size of your plant. In general an application of about 1 tablespoon per ft, up to one cup of fertilizer, is sufficient. Consult the fertilizer packet for the precise dose information.
Whether you are applying a liquid or granular fertilizer, don’t just feed the base of the plant. Try to spread the fertilizer around as much of the root zone as possible. Applying a fertilizer just to the base of the trunk can lead to roots becoming undernourished and stunted.
Pruning helps to keep plants healthy and productful. However, the hawthorn tree is a low maintenance addition to the garden. This means that regular serious pruning is not necessary. Don’t prune until your plant is fully established and has grown by at least 4 to 6 ft.
The best time to prune is in either early spring or winter, when the plant is dormant. Pruning during the winter also encourages more flowers to form the following spring.
Regularly pruning helps to keep plants healthy. Focus on decluttering dense areas, particularly at the center of the plant. This enables light and air to reach all areas of your plant.
Wear gloves and a long sleeved top when pruning. You may also want to wear protective glasses.
While pruning, sharp shears can tackle most small branches easily. You may need to use a pruning saw to remove larger parts of the tree. Loppers or clippers can also be used to tackle smaller branches. Your tools should be clean and sharp. This enables you to make clear, precise cuts.
Begin by cutting away broken, diseased or dying branches. To remove a limb, make a clean cut slightly outside the branch collar. If you only want to remove part of a limb, make the cut slightly above a bud or lateral branch. Making cuts just above a lateral twig or bud that faces the direction you want the branch to grow helps to train the growth direction of the plant.
Prune away cross branches and sprouts from the base of the plant. Pay particular attention to overcrowded areas. If branches are allowed to rub against each other the bark can wear away, creating an easy entry point for pests and diseases.
As you prune, aim to open up the center of the plant as much as possible. Enabling air to circulate freely around and through a plant is an easy way to keep it as healthy as possible.
To prune hawthorn as a shrub, cut away any top branches and leaves that threaten to grow too tall. To shape the plant into a tree, prune away the lower limbs. This creates a string, single trunk.
Finally, remove any suckers that emerge from the base of the trunk.
How to Propagate
The easiest way to propagate your own plants is by growing from seed. Hawthorn tree seeds are contained within the plants bright, red berries.
You can collect the fruit, known as haws, from mid October until December. Waiting until the middle of October gives the seeds time to mature and become viable.
Seeds are containers inside the bright red berries. While harvest is easy, you may need to be quick. Birds love to eat May flower berries and can quickly strip even a large tree.
Open the berries to reveal the seed. Wash away any flesh that remains on the seed.
Soak the seeds overnight in warm water. This helps to soften the outer shell of the seed and encourages germination.
To test if your harvested seeds are viable place them in a glass or bowl of water. If the seed sinks it is viable. Floating seeds are not viable and can be placed out for the birds or discarded.
Fill a small pot, 4 inch pots are fine, with fresh potting soil. Sow one seed per pot, to a depth of no more than 1 inch. Cover the seeds and water.
Place the pots in a cool, damp spot in the garden. Placing the pots outside allows the seeds to experience the natural cold temperatures of winter. This is vital if you want the seeds to germinate. The position should also be fairly light.
Seeds should germinate the following spring. However, germination can take up to 18 months.
Following germination, allow the seedlings to grow on, watering only when the soil begins to dry out. Re-pot when necessary. Once the seedlings have grown into healthy saplings they can be planted out in the garden.
Common Hawthorn Tree Problems
If planted in a favorable position, a healthy hawthorn tree is unlikely to succumb to any major issues.
A preventative application of fungicide in the spring helps to prevent anthracnose, leaf blight and rust, if these diseases are common in your area. Similarly a fire blight treatment can be applied in late winter if fire blight is a problem.
If any of these diseases are a major issue in your area, there are a number of disease resistant varieties now available. These include the attractive Winter King and Washington cultivars.
Regularly check your tree for signs of infestation. Caterpillars, aphids, lace bugs scale and borers can all target the hawthorn tree. An application of insecticidal soap or horticultural oil cures most issues. Larger infestations may require more than one treatment.
As well as introducing spots of color, the bright red berries will attract scores of birds to your garden.
The hawthorn tree provides your garden with height, structure and attractive flowers. They are also a popular draw with songbirds, who love the bright berries that the tree produces. Easy to care for and pleasingly resilient, the hawthorn tree is a rustic but reliable addition to any garden.