Dappled Willow (Hakuro Nikishi)
Ornamental willows grafted on high stems such as the harlequin willow are extremely popular. To keep them compact, they need to be pruned regularly.
The harlequin willow (Salix integra ‘Hakuro Nishiki’) is a colourful, leafy cultivated form of the willow species Salix integra, which originates from East Asia. It was introduced to Europe in 1979 by Harry van de Laar from Japan and since then has enjoyed great popularity as an ornamental plant for the garden. It is also sometimes found in the trade as Japanese ornamental willow, colourful willow or flamingo tree.
The harlequin willow is either grown as a shrub or grafted as a high-stem on to another type of willow. As a shrub form it reaches a height of up to three metres and a width of up to 1.50 metres. High-stemmed willow does not grow very tall, but its crown and trunk become wider over the years. The branches of Salix integra are long, flexible and slightly overhanging at the ends. At up to 30 centimetres a year, the harlequin willow grows rather slowly compared to other willow species. It is also not particularly long-lived: after 10 to 20 years the plants begin to age considerably.
The foliage of the harlequin willow is its greatest ornamental value: the elongated leaves – untypical for a willow tree – are arranged in opposite or whorled rows and are white and medium green variegated. They are also pinkish-red when shooting. The different colour of the shoot tips makes it look as if the harlequin willow is flowering. The sunnier the location, the more intense the colouring of the leaves. In the course of the year the leaves turn green. In winter, the harlequin willow finally shed its leaves, but then remains attractive with its yellowish or reddish shimmering branches.
Like all willows, the harlequin willow is dioecious and forms almost exclusively male, yellow flower catkins which are pollinated by the wind. The catkins appear – at least in theory – between March and April before the leaves shoot. Since harlequin willows are usually cut back heavily every spring, one hardly sees any flowering specimens in the garden. Most hobby gardeners do without the rather inconspicuous flowers in favour of a particularly splendidly coloured leaf shoot.
From June onwards, the female flower catkins of the wild species develop hairy capsule fruits two to three millimetres in size. However, since the ‘Hakuro Nishiki’ variety is a purely male variety, it does not produce any fruit
The harlequin willow has light-coloured foliage and is therefore well suited to sunny locations, as long as it does not get too hot at midday. It also thrives in partial shade, but then the foliage loses some of its brightness.
The optimal soil for ‘Hakuro Nishiki’ is fresh to moist and loose. In very sunny locations it suffers from leaf burns if the soil is not moist enough. The flat-rooting plant does not tolerate waterlogging well. In the tub, the harlequin willow is placed in high-quality tub plant soil.
The harlequin willow is usually planted either in autumn or in spring, but container plants can also be used all year round. After planting, the harlequin willow must be well watered. In hot summers, freshly planted specimens should occasionally be watered additionally. The tree can be transplanted without any problems even after several years, as it will grow again very easily at the new location. The ideal time of year for transplanting is autumn – so the harlequin willow has enough time to take root until the following spring.
Especially trees planted in tubs need regular watering. In dry weather the harlequin willow rolls up its leaves. It is best to use rainwater or well-stable water for watering. A little compost during planting is sufficient to fertilize the willow. Potted plants are happy about a dose of complete fertilizer for leaf emergence. After August no more fertilization should be applied. A mulch layer around the stem reduces evaporation.
The harlequin willow is very tolerant of cutting. The cut is adjusted according to the growth form. High stems usually have a broad, spherical crown. It is important to preserve this crown. The harlequin willow is also suitable for other topiary variants. If it grows as a shrub, it is pruned to the desired size from the third year onwards. Up to two-thirds of the shoot length can be removed without hesitation, if necessary, considerably more. Dead and disturbing branches are removed directly from the trunk. The best time for pruning is on a frost-free day in late winter. If you prune once or twice during the summer, the crown will grow nice and compact. Regular pruning is good for the harlequin willow, because old specimens tend to turn green without pruning. In an emergency, a harlequin willow shrub (not the high-stemmed one!) can also be placed on the cane – this is called radical pruning up to two hand widths above the ground.
Salix integra ‘Hakuro Nishiki’ is fully hardy when planted out and does not require any special protection. Only freshly planted young plants in rough locations should be covered with leaves and brushwood in the root area as a precaution. It is also advisable to shade the stem against frost cracks. As a potted plant, the harlequin willow must always be wrapped up over the winter months to prevent the pot ball from freezing through. When moved close to the house and wrapped in fleece, the stem can then overwinter outside in a pot.
Due to its glamorous leaf colouring, the harlequin willow is perfectly suited as a solitaire. As it does not grow very large, it is an ornament for every front garden and a good choice when space is limited. The harlequin willow also has a great effect in perennial beds. In combination with other woody plants, the shrub has a light and airy effect. As a potted plant for the front garden or terrace, high-stemmed plants are particularly impressive. Underplant the harlequin willow with lavender, cranesbill, horned violet, forget-me-not or foam flower. In combination with early bulb flowers, the early bloomer welcomes the garden year.
Shrubby harlequin willows can be propagated in summer by cuttings. Simply place about 15 centimetres long, diagonally cut head or partial cuttings in an opaque container with water until they form roots. Then place the offspring in pots with a mixture of soil and sand. In spring, the willow cuttings can then be planted directly into the bed. Better results are achieved if the young willow is only in the pot for a few years before planting.
If you want to propagate a high-stem willow yourself, you should grow the high-stem willow in the first winter by simply sticking a long straight rod of a wicker willow (Salix viminalis) into moist, humus-rich soil. After the growing year, the little stem is cut off in the following January at the desired crown height and grafted with a scion of the rakekin willow. Suitable grafting methods are the so-called goat’s foot plug and the plug in the gap. However, both methods require some practice. After grafting, the rice is fixed with bast and the wound including the top of the stem is spread with tree wax. A freezer bag protects the graft rice from drying out. It is removed after the buds have sprouted.
Diseases and pests
If the tips of the leaves turn brown, it is too hot or the plant has too little water. Fungal infestation (rust, willow scab or willow anthracnose) occurs in May or June after a wet spring. It manifests itself by rapid withering as well as scabby, black shoot tips and bark spots. The branches become brown and wither. In this case, cut the shrub back completely to the old wood and dispose of the cuttings in the household waste. To prevent a new infection next year, a fungicide should be applied after the leaves have sprouted. The willow leaf beetle occasionally appears as a pest.
Frequently asked questions
When can you plant a harlequin willow?
Harlequin willows are usually planted in spring or autumn. Container plants can in principle be planted all year round
What can the harlequin willow be fertilized with?
For the harlequin willow it is perfectly sufficient to add some compost when planting. Tub plants should be supplied with a complete fertilizer every year when the leaves sprout. After August, no more fertiliser is applied.
How high will the harlequin willow grow?
If the harlequin willow grows as a shrub in the garden, it can grow up to three metres high and about one and a half metres wide. As a high-stemmed shrub it does not grow very tall, but the stem and crown become wider over the years.
When can a harlequin willow be cut?
A harlequin willow is best cut on a frost-free day in late winter. If you re-cut once or twice in summer, you can look forward to a dense and compact crown.
- Growth type
- Deciduous trees
- Small tree
- Growth height
- from 250.00cm to 300.00cm
- Growth width
- from 100.00cm to 150.00cm
- Growth characteristics
- Flowering time (month)
- March to April
- Flower characteristics
- Leaf colour
- Sheet shape
- full page
- oblong to ovoid
- Leaf characteristics
- Sprout colouring
- Fruit characteristics
- sunny to semi-shady
- Type of soil
- sandy to loamy
- Soil Moisture
- fresh to moist
- slightly alkaline to slightly acidic
- Lime tolerance
- Nutrient requirements
- moderately nutrient-rich
- Decorative or utility value
- Leaf decoration
- Single position
- Form cut
- Rose companion
- Garden style
- Roof garden
- Formal garden
- Rose Garden
- Pot garden