Hakuro-nishiki Dappled Willow
Salix integra ‘Hakuro-nishiki’ Dappled Willow
Known by many names, the colorful dappled willow continues to grow more popular in home landscapes.
Once hard to find, it is now widely available. But every season, there have been more questions about the care of ‘Dappled Willow’ shrubs and trees than any other subject. I will try to answer all those questions.
Finding complete information has been difficult in the past, to say the least.
I first took an interest in the ‘Hakuro-nishiki’ willow shrub back in the nineties and at that time, a great deal of research produced very little information.
Until recently, the information was incomplete and conflicting in some cases. But there are over 300 species of trees and shrubs in the willow family, many species and cultivars being difficult to identify and often mislabeled even in field studies.
Apparently, inaccuracies in Salix identification and nomenclature has been long-standing, and the clarification of cultivar names and information has begun in recent years.
The widespread use of the variegated dappled willows and other dwarf willow forms has encouraged some accurate collection of data. However, it still seems to be scattered among many sources.
Characteristics and Growth of Dappled Willow (Salix integra ‘Hakuro-nishiki’ )
‘Hakuro-nishiki’ is synonymous with ‘Albo-maculata’, also commonly named ‘Dappled Japanese Willow’ or ‘Variegated Willow’.
It may also be marketed as ‘Fuiji Koreangi’, ‘Fuiji Nishiki’, or ’Albomarginata’.
It is one of the smaller members of the willow family, grown as a small tree form or large shrub.
Physical Features: Catkins, Foliage, and Stems
Delicate catkins, which are a yellowish pendant, appear in early spring, usually April, just before the leaves unfurl.
Willows tend to leaf out as much as 4 to 6 weeks before most woody plants.
Foliage is deciduous, emerging pink in spring and maturing to variegated creamy white and green, giving the foliage the dappled appearance.
The leaves are delicate oblong shaped, up to 4” long. The long narrow leaves borne on graceful branches flutter in breezes, showing off the grace of the bush as well as the varied leaf colors.
The leaves eventually turn yellow in fall and will drop quite late, perhaps October or November.
Stems turn red in winter, continuing the colorful interest for your landscape or garden. Best foliage color is achieved in cooler summer climates north of zone 7, making the dappled willow an ideal choice for northern and Midwest gardens.
Pruning will encourage more colorful foliage, as it results in new growth. Pruning may also improve the red branch color for winter, as the newest growth is the reddest.
In the coldest regions, zones 4 and 5, only the new growth will turn coral red. The entire length of the branches will turn coral and red in warmer climates.
Grafted Tree Form and Pruning Techniques
Salix integra ‘Hakuro-nishiki Dappled Willow’, as well as other dwarf shrub willows, are available as a tree form. These are grafted to a compatible, strong and straight growing, upright willow trunk.
The growth structure of the dappled willow and other grafted dwarfs is not strong or sturdy enough to prune to tree form. Any shoots from the trunk or roots should be removed as quickly as possible.
They can eventually overtake and choke the grafted top if allowed to grow, and of course, will not produce the variegated foliage of the graft.
The grafted portion, the tree top, can be pruned as desired when dormant, in late winter or very early spring before any new growth has begun.
Continued shearing through the season will encourage constant new growth to maintain the colorful foliage and the desired form.
Soil, Water, and pH Preferences
Grow ‘Hakuro-nishiki’ in moist, fertile, well drained soils. It will tolerate poor soil, somewhat sandy soil or clay soil but may not produce ideal growth and color.
Dappled Willow trees and bushes will thrive in moist soils, but will tolerate drier conditions once established better than many other willows. It will also do fine if the soil is occasionally wet.
Do not over water, just try to maintain a regular water schedule by supplementing rainfall. And do not let your willow dry out completely between waterings for best health.
Make sure your dappled willow receives consistent water in its first year while it establishes a good, deep, root system. It will also want consistent water during its spring growing season.
Dappled willow will tolerate salt well so ‘Hakuro-nishiki’ is a nice choice for street and boulevard ornamental trees. A slightly acidic to alkaline pH is preferred, from 5.6 (acidic) to 7.8 (mildly alkaline).
Although willows are somewhat adaptable, a combination of adverse conditions will be detrimental to the plant's health. For example, prolonged heat, drought, and compacted clay soil can be damaging.
Sunlight and Shade Requirements
Dappled willow trees and shrubs will grow well in full sun, part sun, or part shade. Best color is produced in full sun. But in zones with hotter summers, the dappled willow will not tolerate prolonged heat.
It is best to plant in part sun or part shade and water weekly where summers are long, hot, and dry. Afternoon shade will protect your dappled willow from the hottest sun of the day in warm climates.
Plant your willow in very early spring before the earliest plants have leafed out, or in mid to late autumn when the soil is still warm but the air temperatures have cooled.
The tender young shoots of a dappled willow seem to be a favorite of rabbits, so you may want to cage in your new plant with chicken wire to prevent nibbling.
Once the willow is established and growing rapidly, a little nibbling won’t be a problem.
Growth Habit and Mature Size
Growth habit of the dappled willow shrub when young is upright, and outward in all directions. As the plant matures, branches will arch gracefully.
It is quite elegant with the drooping branches, delicate-looking variegated leaves, and dangling catkins. It is almost a shame to shear back the elegant foliage just to produce more colorful growth.
You may prefer to cut back only several branches to about half or more to maintain the lovely form and still produce new colorful foliage.
In ideal conditions, the mature height of the dappled willow shrub will be about 10 feet.
Generally, projected growth reaches 4-6 feet in height. ‘Hakuro Nishiki’ is a little slow to establish, but then grows quickly at a rate of 12-18’ per year.
Pruning Techniques and Maintenance
‘Nishiki’ willows take to pruning and shearing very well, to either promote good color or maintain a manageable size.
Pruning should be done while dormant, in either early winter or VERY early spring before catkins appear and any growth begins.
You may hard prune it down to about 12” every few years, which will produce a lot of regrowth and a very dense plant.
If you prefer a more open and natural form, simply remove up to one third of the branches down to the ground each year or two.
By thinning rather than shearing, you will have an 8-10 feet tall and wide, elegant fountain of gorgeous variegated foliage. Or shear as needed to maintain size, or every 4-6 weeks to produce new colorful growth.
Developing Trunk-like Branches and Maintenance
Eventually, your dappled willow (shrub form) will develop thick central branches that become trunk-like, particularly if you are not pruning hard every year.
The old trunks no longer turn red in winter, but do produce many, many branches that turn red.
Growth will be dense to the ground, or you can remove branches up a length of each trunk, resulting in a multi-stemmed semi-tree form.
Maintenance pruning is generally necessary as twigs develop up the length of the bared trunks.
If there are too many main trunks, a few may be pruned out completely, depending on the form you desire.
Fertilization Recommendations
Fertilize dappled willow with a general-purpose fertilizer very early in spring before any growth begins. Somewhat heavy fertilization will help maintain its foliage color, but don't overdo it.
Just be sure to fertilize each and every spring, being somewhat more generous than you would for other low-maintenance shrubs. This will ensure your dappled willow remains healthy and vibrant throughout the growing season.
Enhancing Foliage with Contrast
The beautiful foliage is best set off against a dark background. For a striking display, plant beside or in front of deep purple foliage plants such as a ‘Black Lace’ elderberry or Purple Smokebush.
Japanese willow is an excellent choice for a specimen plant in a large open space or near a water feature, hedge, screen, or windbreak. They will thrive in low areas that are generally more moist.
Dappled willow will also do a very nice job of erosion control on slopes and banks. When sheared frequently to maintain size, the bush can be well used as a bed or border plant, or as a foundation planting.
‘Hakuro Nishiki’ will also do well in a very large container, as will other dwarf willow shrubs.
Willow Roots and Septic Systems
The very large tree form species willows have not been recommended for home landscaping due to their invasive, water seeking roots and weak wood.
The root systems, which are excellent at seeking out moisture, can be particularly damaging to septic systems.
The root systems of the dappled willow and dwarf shrubs, although well developed at maturity, do not compare to the size of a full size willow tree.
The tree form ‘Hakuro-nishiki’ has been grafted to the trunk of another willow variety, and therefore will have a larger, more extensive root system than the shrub.
Although there is little information available regarding damaging roots from the trunks used for grafting, these grafted tree forms were developed specifically for use in small home landscapes.
It is highly doubtful that a trunk would ever be used from one of the very large willow trees that can be so damaging to septic tanks.
Willow roots in general grow very fast, just like the willow plant. They can grow several feet per year and will usually spread equal to their height (a mature ‘Hakuro Nishiki’ may reach about 10 feet).
In general, willow roots are invasive and can exceed the width of the tree’s branches as much as 3 to 4 times. But again, that refers to the large tree form willow.
If you have a septic system and are concerned, why stress? Plant your grafted tree in a very large container, or at least at a great distance from the tank and pipes.
Willow Diseases and Insect Infestations
All willows, the Dappled Willow shrubs, and grafted trees included are susceptible to disease problems which include blight, crown gall, fungus, root rot, cankers, rust, Willow Scab, leaf spot and powdery mildew.
They may also be afflicted with insects including aphids, scale, borers, lace bugs, beetles and caterpillars.
If your willow has been affected by insect or disease, or winter injury, remove all affected branches.
You may severely prune out all damage, leaving very little healthy plant if necessary. The problem may be overcome by the complete removal of afflicted branches.
Thinning out a third of the oldest branches to the ground every year or two may reduce problems, as older wood is more susceptible to disease and pests.
Common Issues for Dappled Willow
The family of willow is susceptible to a long list of insects and disease but they are not necessarily particularly damaging much less fatal to the plant.
A few of those may specifically be common for the Dappled Willow.
Anthracnose diseases are fungi that can cause defoliation (leaf drop) to several types of trees, including the willow. The damage usually occurs after cool wet periods during bud break. A single attack will generally not be harmful, but yearly infections will definitely reduce growth and may contribute to the tree's demise.
Rust causes small brown powdery areas of fungus on leaves and stems.
Aphids leave a sticky sap on the leaves, which can then be afflicted with a black sooty mold. A serious infestation will leave the plant vulnerable to other pests and disease. The aphids are usually small fat green insects, about 2mm long, but may also be black, yellow, pink, or brown.
Caterpillars eat the leaves, quickly leaving an unsightly plant.
Leaf beetles strip the tissue of leaves, leaving leaf veins exposed. There are various beetles that attack willows (and poplars). They are small, ‘metallic’ blue, brown or brassy and about 4-5mm long.
Sawflies larvae eat leaves, causing extensive damage. The adult is up to 10mm long with 2 pair of wings and dark bodies and legs. They may look like flying ants.
Propagating Dappled Willow
Dappled willow can be propagated from softwood or semi-hardwood cuttings. To produce new plants, just plant 8” cuttings of stem without leaves into consistently moist soil in a small pot or nursery bed, they will generally root easily.
When the roots become visible through the drainage hole in the pot they are ready to plant in the ground.
Willows root fairly quickly, and cuttings potted in October should be ready the following spring.
Full grown dappled willows also transplant quite successfully. A large plant should be cut back to about 12” in very early spring or late Autumn, then moved to a new planting hole.
Climate and Winterization
Salix integra ‘Hakuro-nishiki’ Dappled Willow is hardy in zones 4-9. However, particularly cold winters in zones 4 may cause loss of much of its variegation the following season.
Shearing and fertilization will help to regain the colorful foliage. Since the dappled willow is hardy up to zone 4, you should not need to do anything special to winterize your dappled willow.
Do follow standard practices to winterize shrubs and trees in cold climates: Water regularly and thoroughly in autumn to allow the plant to take in as much water as it needs, it will naturally decrease water intake as freezing weather approaches. And do NOT fertilize after about mid-August. Fertilizing will encourage new growth, which freezing temperatures may damage.
Indoor Arrangements with Dappled Willow
When you do prune your dappled willow, take some of those beautiful branches inside for a fresh arrangement.
They are quite lovely in a bunch on their own, but they also are great as a filler and to add height in a vase with other cut flowers and branches.
For a striking arrangement, put a few dappled willow branches in a vase with delphinium or lupines.
Quick FAQs
Here are some questions that are more specific to variable conditions that may affect growth.
Despite being watered, the leaves of my dappled willow are drying up and appear to be dry
It's highly probable that your dappled willow is indeed experiencing dryness. These trees require soil that is consistently moist, but not overly saturated. The frequency of watering necessary will depend on various factors such as soil quality and weather conditions.
However, a general rule of thumb is to water your tree on a weekly basis, but avoid watering it lightly and frequently. Instead, give it a thorough soak each time.
If the weather is particularly hot and dry, or if your soil is not very good at retaining moisture, then you may need to water it more often, such as every four or five days.
Conversely, if the conditions are less severe, you may be able to water it less frequently, but be sure not to let the soil dry out completely.
Is it possible to overwater my dappled willow? And if so, what are the symptoms to look out for?
Yellowing leaves are typically the first sign of overwatering. If the wet conditions persist, the leaves will start to drop. However, it's worth noting that symptoms of overwatering, drought stress, and root rot fungus can be quite similar.
These conditions usually start with yellowing leaves, followed by leaf drop and eventually limb dieback. To check if your tree is being overwatered, poke the soil with your finger - if it feels moist, stop watering until the soil starts to dry out quite deeply. Once it does, water generously, but avoid watering again until the soil starts to dry out once more.
If your tree begins to improve, overwatering was likely the issue. However, if it hasn't improved, it's best to wait as long as possible for signs of improvement. Sometimes, the best thing to do for a sick plant is to do as little as possible.
If the condition worsens, it could be one of the many diseases that affect willows. In such cases, take some clear, close-up pictures and a few freshly cut branches to a reputable local nursery for a diagnosis.
Lastly, consider whether you fertilized your dappled willow in the spring - these trees tend to do best with a generous dose of general-purpose fertilizer during this season. If you notice yellowing leaves with no other symptoms, a lack of fertilizer may be the cause.
Will pruning keep the roots on my ‘Hakuro-nishiki’ small?
To my knowledge, keeping the top growth of a willow tree small will not have a substantial impact on the root system, although the general rule of thumb is that the root spread will typically be at least as wide as the branches spread.
For larger willow trees, the root spread can be even greater. However, if you consistently prune a 10-foot shrub to just 2 feet in height, it's possible that the root growth may be somewhat stunted because the plant won't require as much root to support it.
If you're worried about willow roots causing issues with septic tanks or water lines, please refer to the information provided above.
When should I plant a Japanese Willow?
For optimal results, it's recommended to plant your shrubs and trees during early spring or autumn when the temperatures are cooler, as this reduces the likelihood of the plant and soil drying out too easily.
It's important to keep in mind that planting can be a stressful experience for the plant, so it's best to avoid exacerbating this by planting on a day that's hot, dry, or windy.
However, most shrubs and trees can be planted at any time of year with proper care, even in the middle of summer. However, those that struggle to tolerate long, hot summers even after becoming established may experience difficulties.
Therefore, if it's already summertime, it's advisable to wait until fall or spring to make things easier on both yourself and the plant.
Can I transplant my dappled willow?
Yes, they tolerate transplanting quite well. Take note of when best to plant in the previous question. If your shrub is already quite large, reducing the size will make it easier to manage.
My variegated willow is reverting to all green - the foliage on a few branches is completely green. Is there anything I can do?
Plants with variegated foliage, such as the variegated Norway Maple, have a tendency to revert, but this can also be an issue with dappled willows. Fortunately, there are a number of things you can do to minimize the occurrence of this problem.
Firstly, you should prune your tree frequently as the colorful variegation is most noticeable on new growth.
Secondly, for the best color, it's important to plant your dappled willow in full sun, unless you live in a hot area with prolonged dry spells.
Thirdly, fertilizing your tree each spring with a general purpose fertilizer will help to encourage good color. If your soil is particularly poor, you may need to fertilize again 6-8 weeks later.
Lastly, you should remove branches that have all green foliage. These limbs tend to grow most vigorously and if left unattended, they will overtake the variegated limbs.
Are the dappled willows susceptible to disease?
Information on the specific topic of 'Hakuro-nishiki' dappled willow is somewhat scarce. However, it's worth noting that the general species of willow is susceptible to a range of diseases and insects, some of which may have a particular impact on dappled willows, as previously mentioned.
It's unclear whether 'Hakuro-nishiki' is a cultivated variety that has been improved by human intervention or hybridization. Typically, hybrid plants are developed to incorporate the best characteristics of different plants and enhance disease resistance.
'Flamingo', a variety of Salix integra, is an example of an improved version of 'Hakuro-nishiki', but it was not created through hybridization. Instead, it arose from a natural mutation of a whole plant.
This variety has some distinct features, such as more upright and spreading growth, smaller and thinner leaves, thicker stems, sunscorch-resistant leaves, and a greater amount of red color in young leaves and branches. However, disease resistance remains the same as the original.
If you suspect that your dappled willow is showing signs of illness, investigate the possible disease and insect culprits mentioned earlier.