Maule's quince bonsai

Placement

Grow Maule’s quince outdoors in full sun: that is the key to heavy flowering. It tolerates partial shade but blooms noticeably less there. Any exposure suits it, and it copes with wind as well as with a sheltered corner.

It must not spend winter somewhere warm. This is one of the most cold-hardy flowering quinces, and it needs a real cold period: without it, flowering is weak or absent. Keep the tree outdoors and never bring it into a heated room, where the sudden change would weaken it. In a pot, though, its roots are more vulnerable than in the ground: during hard freezes, protect the root ball by setting the pot on the ground out of the wind, wrapping it in insulation, burying it in the garden or sheltering it in a cold frame. On sunny winter days, open the cold frame so the tree does not wake too early. Once the buds start growing, protect them from late frosts.

Feeding: feed every two weeks from the end of flowering until leaf drop. A fertilizer slightly higher in phosphorus encourages flowering on flowering trees. Follow the label rates: too much fertilizer harms the tree.

Pests and diseases: watch for aphids on young shoots, scale insects (including brown scale) and mites. In rainy years, a leaf spot disease can defoliate the tree. The species can also suffer from canker, fire blight, blossom wilt and brown rot of the fruit, and more rarely honey fungus on the roots. Leaves that yellow between the veins signal chlorosis, common when the mix is too alkaline.

Soil mix

A standard bonsai mix works, as long as it drains well. A common base combines akadama, pumice and lava rock in equal parts; add more akadama if you cannot water often, or more lava rock in a humid climate. The species tolerates lime but prefers fairly acidic conditions: avoid a very alkaline mix, which causes chlorosis.

Watering

Do not follow a fixed schedule: observe. Push a finger about 0 in into the mix and water when it feels slightly dry. Then water thoroughly with a fine-rose watering can until water runs from the drainage holes, and repeat a few minutes later to soak the whole root ball.

In the ground Maule’s quince tolerates drought, but in a bonsai pot the root ball has no reserve: never let it dry out completely, because fine roots die and the tree weakens. Conversely, constantly soggy soil starves the roots of air. Watering becomes more frequent in spring and summer and much less frequent in fall and winter, when the tree is resting. Rainwater is ideal, but tap water is fine.

Pruning

Everything depends on flowering, which forms on the previous season’s shoots.

• During growth: let new shoots extend freely all summer. Shortening them too early would remove next year’s flower buds.
• Maintenance pruning: in fall, cut the year’s shoots back to the first or second node.
• After flowering: remove spent flowers so the tree does not exhaust itself making fruit, unless you want to enjoy the small yellow quinces in fall. Remove suckers and shoots rising from the base, unless you need them for a multi-trunk style.
• Structural pruning: avoid severe cuts; if a thick branch must go, remove it right after flowering and seal the wound with cut paste.

Wear thick gloves: the twigs are covered in spines.

Styles: multi-trunk, clump and sinuous forms are the most common. It suits most styles except formal upright and broom, and is grown mainly in small and medium sizes. A plant raised in a container often keeps a thin trunk: a few years in the ground thicken it before training.

Propagation: sow seeds outdoors in fall, take semi-ripe cuttings in midsummer, or layer a branch in fall.

Wiring

Wire in late winter, when the tree is bare and its structure is easy to read. Choose anodized aluminum wire, which suits deciduous trees, about a third the thickness of the branch, and wind it at roughly 45 degrees. Work carefully around the spines.

Branches usually set within a few months, but wire can cut in within one to four months during growth. Check it regularly and remove it before it marks the bark, snipping it at every turn rather than unwinding it.

Repotting

Repot every two to three years. Fall is the preferred season; spring repotting is also possible, with care, before the leaf buds lengthen. If roots are circling the root ball, it is time. Trim overly long roots without removing more than about 30 % of the root mass, then set the tree in fresh mix. Afterward, keep it out of wind, harsh sun and frost, keep the mix moist, and wait for recovery before feeding or pruning hard.