Midland hawthorn bonsai

Placement

Midland hawthorn is grown outdoors year-round: like all temperate trees, it needs the change of seasons. It thrives in full sun or partial shade; a bright spot is still the rule, with some afternoon shade if your summers are very hot.

Very frost hardy, it also tolerates cold winds. In a small pot, though, its roots are more exposed, so protect it from excess winter rain and hard frost. Wait for the first frosts before moving it under cover, so it goes fully dormant. Where temperatures often drop below 14 °F, overwinter it in a cold frame or unheated greenhouse; in milder climates, with nights around 25 °F, simply set the pot on the ground out of the wind, perhaps wrapped in insulation. Don’t overprotect it by bringing it into the living room, either.

Soil mix

Choose a standard, well-draining soil with a neutral pH. A mix of 50% akadama, 25% pumice and 25% lava rock, the usual base for deciduous trees, works well; add a little more akadama if the tree dries out too fast, or more lava rock in a humid climate. Sift the akadama to remove dust, which clogs the pot.

Watering

During the growing season, Midland hawthorn needs plenty of water and its roots must never dry out, or the leaf tips turn brown. In winter, just keep the root ball slightly moist. Never water on a routine: check the soil with a finger about 0 in deep and water as soon as it feels slightly dry, soaking the whole root ball until water runs from the drainage holes. It copes with a fairly wide pH range but dislikes very hard, calcareous water, so rainwater is ideal.

Fertilizer: throughout the growing season, apply a liquid fertilizer every week or a solid organic fertilizer every four weeks. Choose a balanced product with enough phosphorus, potassium and micronutrients to encourage flowers and fruit.

Pruning

Midland hawthorn takes pruning very well, branches readily and even buds back on old wood. Its buds, however, are not determined in advance: depending on conditions, they become flowers, thorns or leaves. After hard pruning or heavy root pruning, buds that would have flowered produce leaves instead.

Prune older branches in early spring and seal the cut with cut paste, so the bark does not die back around the wound: large wounds take years to close. Structural pruning can also be done after flowering or after leaf drop. The tree concentrates its vigor at the top, so prune the crown harder than the lower branches, and cut just above a bud.

During the growing season, let young shoots reach 4–6 in, then cut them back to two or three leaves. You can also pinch out shoot tips in spring, or shorten them by three quarters, but not too early, or you will lose the flowers. Don’t keep cutting back to the same point, which creates ugly knobs. Repeated clip-and-grow builds fine ramification. The trunk thickens slowly; a hawthorn can live around five hundred years.

Wiring

Midland hawthorn branches are fairly flexible and easy to wire, but watch out for the thorns: it is often best to remove them before applying wire. Do heavy wiring during winter dormancy, when no leaves are in the way. Young shoots can be wired during the growing season, before they harden. Shape old, stiff branches with guy wires.

Choose wire about a third as thick as the branch, wrapped at 45°, and protect thick branches with damp raffia. Check often: wire can scar the bark within one to four months. Remove it by cutting it at every turn, never by unwinding it.

Repotting

Repot every two or three years in spring, before growth begins. You can remove up to a third of the roots, but remember that heavy root pruning reduces the following bloom. Tease out the old soil with a chopstick, secure the tree to the pot with anchoring wires, water thoroughly and keep it out of strong sun and wind while it recovers.

Midland hawthorn suits almost every style except broom and formal upright. It propagates from seed in spring or semi-hardwood cuttings in midsummer; air layering usually fails, and cultivars are grafted by professionals. Old trees dug from hedges or the wild establish poorly and many die: you need the landowner’s permission, should dig in early spring, then keep the tree in shade, damp but not wet, and leave it untouched until the following spring. Watch for aphids, scale, caterpillars, vine weevil larvae, gall mites, rust, powdery mildew, leaf spot and fire blight.