Hamamelis × intermedia 'Arnold Promise'
Arnold Promise Witch Hazel
Garden origin (hybrid; parent species native to Japan and China)
Overview
Hamamelis spp. 'Arnold Promise' is a deciduous hybrid witch hazel, a cross of H. japonica and H. mollis, grown for late-winter bloom. It forms a large, vase-shaped shrub or small tree 12-15 feet (3.7-4.6 m) tall and wide, with spreading branches. The flowers open in late winter, typically February to March, each with four narrow, crinkled, strap-shaped petals about 0.6 inch (1.5 cm) long in bright yellow, clustered along the bare stems and carrying a sweet fragrance. The petals roll up during hard freezes and reopen as temperatures rise, extending the display over several weeks. Autumn foliage turns yellow before dropping. It is hardy in USDA zones 5-8 and needs space for its broad mature spread, which makes it large for small gardens. It grows in full sun to part shade in moist, acidic, well-drained soil; bloom is heavier and fall color stronger in more sun. Most plants are grafted, and shoots from the rootstock will overtake the named top if left in place.
Native Range
Hamamelis spp. 'Arnold Promise' is a cultivated hybrid with no wild range, raised at the Arnold Arboretum from a cross of H. japonica and H. mollis, both native to East Asia. It was selected for its bloom and form rather than collected from the wild.Suggested Uses
Used as a specimen, in shrub borders, and at woodland edges where the late-winter flowers and autumn color show, spaced 12-15 feet (3.7-4.6 m) apart. The broad mature size makes it large for tight foundation beds.How to Identify
Appearance
Size & Dimensions
Height12' - 15'
Width/Spread12' - 15'
Reaches mature size in approximately 10 years
Bloom Information
Flowers open in late winter, usually February to March depending on region, before the leaves emerge. The strap-shaped petals curl shut during hard freezes and unfurl again in milder spells, so bloom can span four to six weeks. The fragrance carries on warm late-winter days.
Detailed Descriptions
Foliage Description
Mid-greenGrowing Conditions
Sun Requirements
Requires 4-8 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Care & Maintenance
Care Guide
This shrub grows in full sun to part shade, with heavier bloom and stronger fall color in more sun. It needs moist, acidic, well-drained soil rich in organic matter at a soil pH of 5.0-6.5 and does not tolerate dry or alkaline ground. Even moisture suits it, and a 2-3 inch (5-8 cm) mulch keeps roots cool. Most plants are grafted, so shoots arising from below the graft are removed before they overtake the named top. Little feeding is needed beyond an annual mulch of compost.Pruning
Pruning, if needed, is done right after flowering in late winter to early spring, removing crossing or crowded branches to keep the vase shape open. Suckers from the rootstock are cut away at the base as they appear. The plant flowers on established wood and needs little routine cutting.Pruning Schedule
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F
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A
M
J
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A
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early spring