'Arnold Promise' (Hamamelis x intermedia 'Arnold Promise') is one of several popular named cultivars derived from a hybrid cross between Japanese witch hazel (H. japonica) and Chinese witch hazel (H. mollis). 'Arnold Promise' and related cultivars are becoming more common in landscape use than the native witch hazel species. These cultivars are often grafted onto the rootstock of native H. virginiana, resulting in a plant that may produce unwanted suckers—but this is the one complication of an excellent shrub that is otherwise very easy to grow.
'Arnold Promise' is a deciduous flowering shrub that is prized for its spidery bright yellow blooms that arrive in late winter or early spring, before the foliage opens. This may well be the first flowering plant of spring, sometimes blooming while snow still blankets the ground. This cultivar has a low branching, vase-shaped growth habit, and 6-inch-long oval-shaped leaves with toothed edges. The foliage turns an attractive yellow-to-orange color in the fall.
These shrubs have an average growth rate, requiring several years to reach 15 feet in height. They are best planted in fall, though they will do fine with a spring or summer planting, provided that you water frequently and deeply.
|Botanical Name||Hamamelis × intermedia 'Arnold Promise'|
|Common Name||'Arnold Promise' witch hazel|
|Plant Type||Deciduous flowering shrub|
|Mature Size||12 to 15 feet tall; similar spread|
|Sun Exposure||Full sun to part shade|
|Soil Type||Average, medium-moisture well-drained soil|
|Soil pH||4.5 to 6.5 (acidic; but will tolerate neutral or slightly alkaline soil)|
|Bloom Time||Late winter or early spring|
|Hardiness Zones||5 to 8 (USDA)|
|Native Area||Hybrid plant; parents are native to Japan and China|
How to Grow 'Arnold Promise' Witch Hazel Shrubs
'Arnold Promise' is a largely care-free shrub with a low-branching habit that allows the shrub to take on the appearance of a small tree as it reaches full maturity. The most challenging maintenance task is to simply remove any suckering shoots that appear below the graft point, in order to preserve the integrity of the shape.
This variety requires little in the way of feeding or pruning, and it doesn't even require much watering once the shrub is fully established. The occasional problems that do occur are largely cosmetic and may include caterpillars and Japanese beetles chewing on the leaves, and powdery mildew and occasional leaf spots.
European settlers in the New World used the branches of witch hazel trees as divining rods for dowsing. The "witch" name derives from the Anglo-Saxon wych, meaning "bend"—which is what a divining rod is supposed to do when it detects water.
Plant 'Arnold Promise' where it will receive at least 4 hours of sun daily; flowering will be better in a full-sun location that receives at least 6 hours of sun each day. Shadier conditions may lead to a somewhat spindly plant.
This shrub, like all witch hazels, prefers an organically rich, moist soil with good drainage. It will tolerate clay soil provided it is well-drained. Witch hazels prefer acidic soil but normally will tolerate neutral to mildly alkaline soil.
Witch hazels should be watered frequently for the first two or three years until they become established. After this, they require watering only during dry spells.
Temperature and Humidity
The hybrid witch hazels are hardy from USDA zone 5 and southward, and will survive temperatures down to minus-10 degrees Fahrenheit. These are not good plants for regions warmer than zone 8, though the 'Diane' cultivar grows well into zone 9. These plants require a period where temperatures fall below 45 degrees in order to bloom and aren't a good choice in regions where temperatures don't reach this level. Within the hardiness range, these shrubs will tolerate both dry and humid conditions, provided the soil is kept moist.
Mature shrubs generally don't require any feeding at all. Young plants may respond well to being top-dressed with a granular balanced fertilizer in late winter or early spring. Soil that is too alkaline may benefit from applying an acidifying fertilizer.
Pruning 'Arnold Promise'
To maintain the attractive vase shape, the suckers appearing at the base of the plant should be pruned away as they appear below the graft point. These suckers are usually shoots from the rootstock, and they will not have the same attractive flowers as the grafted upper portion of the shrub.
Pruning the upper branches for shape should be done immediately after flowering is complete in the spring. As with all shrubs, though, any time is a good time to prune out dead or diseased branches or branches that rubs against one another.
'Arnold Promise' vs. Other H. Intermedia Cultivars
A number of other Hamamelis x intermedia cultivars are also very popular, offering different colors:
- 'Diane ' (Hamamelis x intermedia 'Diane') is a cultivar that grows somewhat wider than it is tall—8 to 12 tall and up to 15 feet in spread. Its flowers are copper-red in color.
- 'Copper Beauty' (H. x intermedia 'Copper Beauty') has coppery-orange flowers with twisted petals. Fall color is especially dramatic, with a blend of orange, red, and yellow hues.
- 'Ruby Glow' (H. x intermedia 'Ruby Glow') is similar in shape and size to 'Arnold Promise', but the flowers are copper-red and the fall color is a deeper red/orange.
'Arnold Promise' vs. Native Witch Hazels
In addition to these hybrid forms of x intermedia, there are two native North American witch hazel shrubs that are sometimes grown in cultivation, including:
- Hamamelis virginiana (common witch hazel) is a 15- to 20-foot-tall shrub that flowers with yellow blooms from October to December. It is hardy in zones 3 to 8.
- Hamamelis vernalis (Ozark witch hazel) is a 6- to 10-foot shrub hardy in zones 4 to 8. It has yellow blooms with red centers that appear in winter to early spring.
Mix witch hazel shrubs into a bed of other deciduous bushes, situated within sight of a window so you can enjoy an unimpeded view of these beauties in late winter to early spring. You will see an eruption of yellow in the midst of the bare branches of surrounding plants.
Witch hazel plants are showy enough when in bloom to serve as minor specimen plants. After blooming is finished during spring and summer, the bushes are rather ordinary-looking, although the vase-shaped form may be valued in winter by those who appreciate subtlety.