Mirabelle plum

Established mirabelles overwinter outdoors without protection in the lowlands of Germany, Austria and Switzerland. No wrapping, no bringing indoors. For young trees, wrap the trunk in hessian or horticultural fleece against frost cracks in the first two to three winters and lay a layer of mulch or leaves over the root zone; from the third to fourth year you can leave this off.

The most reliable method for propagating a mirabelle true to the cultivar is grafting onto a rootstock. Seedlings grown from stones do not come true to the cultivar and bear fruit only after many years, so sowing is ruled out for propagating the cultivar. Suitable rootstocks are myrobalan (Prunus cerasifera, robust and vigorous, for heavy or dry soils, though it produces suckers itself), St. Julien A (somewhat smaller trees, good for the home garden, produces no suckers, likes better soils) or Wangenheim (growing somewhat less vigorously than St. Julien A). For budding (T-budding onto a dormant bud), in July or August cut a ripe bud from this year's shoot and insert it under the bark of the rootstock. Whip-and-tongue grafting (straight cut on both partners, bound with grafting tape) works in early spring (February to April) before bud break. The rootstock should be about pencil-thick and as close as possible in thickness to the scion.

If you have a mirabelle tree on its own roots (not grafted), you can use suckers for division: in early summer, shoots sometimes appear around the trunk. Lift them carefully with a spade, make sure the shoot already has its own roots, and plant it straight away in its new position. Important: on grafted trees, suckers always come from the rootstock. They will not become a mirabelle, but the rootstock variety.

Cuttings are another option, though with a much lower take rate. In spring, take semi-hardwood shoots about 10 to 15 cm long, remove the lower leaves and insert them in a loose, well-moistened substrate. Put the pots somewhere bright but sheltered from direct sun, and keep the substrate evenly moist. Rooting takes several weeks.