Crataegus x lavalleeiHawthorn
科:蔷薇科
Family:Rosaceae
属:山楂属
common name:Hawthorn
introduce:Plant Type: Tree
Family: Rosaceae
Missouri Native: No
Native Range: None
Height: 15 to 25 feet
Spread: 10 to 18 feet
Bloom Time: May
Bloom Color: White
Sun: Full sun (only)
Water: Medium moisture
Maintenance: Medium
General Culture:
Grow in average, medium moisture, well-drained soils in full sun. Tolerates a wide range of soils as long as drainage is good. Tolerates light shade and some drought. Tolerates many urban pollutants.
Noteworthy Characteristics:
This hybrid hawthorn (C. stipulacea x C. crus-galli) was discovered around 1870 growing at the Arboretum Segrez near Paris, France. The Arboretum was purchased in 1856 by Alphonse Martin Lavallee, 19th century French horticulturist, and thereafter developed by him. This hawthorn is more erect and less densely branched than most other hawthorns. It is a small oval to rounded tree to 15-25?tall and 10-18?wide. It also may grow as a large multi-stemmed shrub. Branching is armed with thorns (to 2?long), but usually fewer thorns than its C. crus-galli parent. Narrow elliptic, irregularly toothed, dark green leaves (to 4?long) turn bronze red in fall. White flowers (in 3-inch corymbs) bloom in May. Flowers emit an unpleasant fragrance. Flowers are followed by ellipsoid fruits (3/8?diameter) that ripen to orange-red in September-October and typically persist throughout winter to spring. Fruits are technically edible, but are usually best left for the birds. The fruit is sometimes called a haw. It should be noted that many people in the plant industry currently spell the hybrid designation as x lavallei.
Problems:
Pests and diseases are a problem with most hawthorns. Plants are susceptible to cedar hawthorn rust (rust stage where eastern red cedars are present in the area) and fireblight. Reportedly, C. lavallei has good resistance to rusts and fireblight. Other potential diseases include fungal leaf spots, powdery mildew, cankers, apple scab, leaf blight and twig blight. Potential insect pests include aphids, borers, caterpillars, lacebugs, leafminers and scale. Red spider mites may also occur. Use of pesticide sprays may be advisable in areas where this plant suffers from significant diseases and insects. Thorns pose significant risks for young children, and also make culture/pruning more difficult.
Uses:
Small flowering landscape tree for lawns or open woodland areas. Notwithstanding disease susceptibility, a well-maintained tree can be ornamentally attractive. Thorns are a drawback for pedestrian areas or areas with small children. Plants may be effective when grown as barrier plants on property borders or in hedgerows.
