Cucumber tree (Magnolia acuminata) is the largest and hardiest of the native North American magnolias, a deciduous tree of 50 to 80 feet with a straight trunk and a pyramidal crown. It is named for its unripe fruit, a knobby green cone that looks like a small cucumber before it turns red and splits to show orange-red seeds. The flowers are yellow-green, 2 to 3 inches, and open in late spring half hidden among the new leaves.
It is a tree for a large property, a park edge or a woodland margin rather than a small yard, and it wants deep, rich, slightly acid soil that holds moisture, in full sun to part shade. Plant it young, since magnolias resent root disturbance, and keep it watered for the first few years. It grows faster than most magnolias and is hardy to zone 4, well north of its showier relatives.
The fall colour is a clear golden yellow. Birds take the seeds, and the tree is a parent of most of the yellow-flowered hybrid magnolias ('Elizabeth', 'Butterflies'), which get their hardiness and their colour from it. Its native range runs from southern Ontario and New York down the Appalachians to Georgia and west to Arkansas.
Ecoregions:Northern ForestsEastern Temperate Forests
Verticillium Wilt
Lower leaves yellow and wilt, often on one side of the plant, with brown streaking in the stem and crown tissue when cut open. Plants are stunted and decline over the season.
Remove and destroy affected plants. Avoid planting in soil that has grown infected tomatoes, peppers, or other susceptible crops. Rotate beds and improve drainage; there is no cure once a plant is infected.
Fungal leaf spot
Brown or purplish spots on the leaves, often ringed with a yellow halo, that spread and merge in warm, humid, or wet weather; heavily spotted leaves yellow and drop early.
Pick off spotted leaves and clear fallen debris to remove overwintering spores. Improve air circulation by thinning, and water at the base so foliage dries quickly. If it persists, apply a copper- or sulfur-based fungicide at the first sign.
Magnolia Scale
Neolecanium cornuparvum →Large brown or pinkish bumps clustered on twigs and young branches. Sticky honeydew coats leaves below, often followed by black sooty mold and stunted growth.
Prune out and destroy heavily infested twigs. Apply horticultural oil to smother crawlers in late summer and dormant oil in early spring. Monitor annually since populations rebuild slowly.