The Hawthorn Bonsai: Rustic Elegance and Red Berries

The Hawthorn (botanical name Crataegus monogyna) belongs to the large Rosaceae family. It is one of the species most loved by European bonsai growers for a simple reason: it is a generous plant. It gives us bark that ages beautifully, delicate white flowers in spring and red berries (drupes) that stay on the bare branches throughout winter. It is a tree "with character", tough and able to forgive the odd small mistake by a beginner, yet capable of becoming a masterpiece in expert hands.

Origin & species

Native to Europe, North Africa and western Asia, the Hawthorn is a shrub or small tree that we often find growing wild in our countryside. The most common species for bonsai is Crataegus monogyna, but Crataegus laevigata also works very well. Its hardy nature makes it perfect for our climates, as it is used to the alternation of the seasons.

Exposure and microclimate

This is a plant that loves light. To obtain abundant flowering and compact growth, the Hawthorn must stand in full sun for most of the year.
However, care is needed in midsummer: in the very hot areas of southern Italy or on the Po Valley plain, light shading during the afternoon hours of July and August prevents leaf scorch. It likes airy positions, which help keep fungi such as powdery mildew at bay.

Watering

The Hawthorn drinks, but it does not like standing water. The golden rule is: touch the soil. Water generously only when the surface layer of the substrate feels slightly dry.
In summer daily watering may be necessary, while in winter watering should be cut back drastically, keeping the soil mix just barely damp to protect the roots from dry frost.

Water quality

It prefers water that is not too calcareous, although it is fairly tolerant. Rainwater or tap water left to stand for 24 hours is ideal. Water that is too hard can, over time, make the soil alkaline, blocking the uptake of micronutrients and causing chlorosis (yellow leaves).

Substrate

The choice of soil mix is crucial and varies according to where you live:

• Humid climate or northern Italy: I recommend a free-draining mix to avoid rot. Use 60% Akadama and 40% pumice.
• Hot climate or southern Italy: Here the sun "eats up" moisture quickly. I suggest adding an organic component to retain water. An excellent mix is: 50% Akadama, 30% pumice and 20% worm humus or high quality universal soil.

Repotting

Repotting is carried out every 2-3 years for young specimens, and every 3-5 years for more mature ones. The perfect moment is the end of winter, just before the buds open (generally between late February and early March). The Hawthorn tolerates root pruning well, but do not overdo it: reduce about one third of the root system, removing the thicker, woody roots in favour of the fine feeder roots.

Fertilising

Flowers and fruit need energy. Use a solid, slow-release organic fertilizer.
Feed in spring (March-June) to push growth and in autumn (September-October) to strengthen the plant ahead of winter. Suspend feeding during flowering so the flowers are not shed, and during the fierce heat of August.

Flowering and fruiting

This is the strong point of the species. The flowers appear in spring, followed by the berries in autumn.
Careful with pruning: flower buds form on the short shoots of the previous year. If you prune too drastically in late winter, you risk eliminating the flowering. To enjoy the fruit, do not remove the spent flowers, but let them set.

Structural pruning

Heavy pruning, the kind used to define the shape and cut thick branches, is done during winter dormancy, when the tree is bare and the structure is clearly visible. Always use cut paste on large cuts, as the Hawthorn struggles a little to close big wounds.

Maintenance pruning

During the growing season, shorten the branches that extend too far to keep the silhouette. Cut back leaving 2-3 nodes once the shoot has lignified.

Pinching

On the soft shoots in spring you can carry out pinching to thicken the foliage pads, but do it sparingly if you want to see flowers the following year. Continuous pinching encourages fine ramification but reduces flowering.

Wiring & bending

Hawthorn wood becomes very hard and brittle over time. Wiring is best done in spring or autumn on young branches that are still flexible. Pay close attention to the bark: it is delicate and the wire can easily mark it. Check often and remove the wire before it bites in.

Diseases and pests

It is a sturdy plant, but not immune.

• Aphids: They attack the soft shoots in spring.
• Powdery mildew: A white film on the leaves, typical of damp springs and autumns.
• Rust: Orange spots on the leaves.
• Scale insect: It often hides in the crevices of the bark.

A preventive winter treatment with diluted jin liquid can help to sanitise the bark.

Winter & protection

The Hawthorn is tough and withstands cold well. However, in the case of intense and prolonged frosts (below -5°C), it is better to protect the pot with horticultural fleece or mulch to prevent the roots from freezing, especially if the bonsai is in a small pot.

Yearly calendar

• January-February: Dormancy, frost protection, structural pruning.
• March: Repotting, start of fertilising.
• April-May: Regular watering, pest checks, enjoy the flowering.
• June-August: Frequent watering, suspend fertilizer (July-August), pinching of green shoots.
• September-October: Autumn fertilising, check the wire.
• November-December: Clean up fallen leaves, dormancy.

Useful products for this bonsai

• Akadama Hard Quality (essential substrate)
• Medium grade pumice (for drainage)
• Organic fertilizer (basic nutrition)
• Precision pruning scissors
• Copper-coloured aluminium wire for wiring
• Cut paste (indispensable on cuts)

Frequently Asked Questions about Hawthorn

Why doesn't my Hawthorn flower?
The cause is often incorrect pruning. If in winter you cut away all the short twigs, you remove the flower buds the plant prepared the year before. Also make sure it gets enough direct sun.

Can I keep a Hawthorn bonsai indoors?
Absolutely not. It is an outdoor plant that needs to feel the winter cold in order to go dormant and direct sun in order to grow. Indoors it would slowly die.

The leaves turn yellow and drop in summer, why?
If it is not autumn, it could be drought stress (too little water) or, on the contrary, root rot (too much water/poor drainage). If the leaves have "burnt" tips, it is often down to too much sun combined with too little water in the pot.

When is the best time to apply wire?
Late spring is a good moment for new branches, but check every week. In autumn, after leaf fall, it is easier to see the structure and wire the older branches, but be careful not to snap them because they are stiff.