Last Updated on October 20, 2022 by Plant Mom Care
Viburnum plicatum, a species of deciduous shrubs with abundant stunning flowers, is indigenous to East Asia. It is widely planted as ornamentals in North America, with some cultivars planted in New England having all their flowers transformed into sterile enlarged flowers in spherical clusters resembling snowballs.
The serrated leaves are arranged with two leaves on each node along the stems and the plant can reach a maximum height of 10 feet.
It is best planted in autumn to promote good root development before winter begins as the roots start spreading underground, preparing the plant for a vigorous growing period in spring and summer. This also helps the plant to start flowering earlier in spring.
While it can be grown as a potted plant indoors, it needs a period of dormancy in winter, so has to be kept in a cool location for it to produce more flowers in spring and potted plants have to be pruned down after flowering to keep their growth down since they don’t like to be transplanted or repotted often.
It is an excellent food source of nectar and pollen for honey bees in spring. The fruit is a small fleshy blackish-red ovoid.
Japanese Snowball Light Requirements
It grows best underneath trees or taller shrubs that can protect it from the harsh sun if you live in hot climates and does well in cooler places with full sun.
A measured amount of indirect light is desirable during its flowering phase to promote continuous flowering in warm climates, but this plant generally performs well with 5-6 hours under the full sun daily. It naturally loses its leaves in autumn in temperate climates as it is a deciduous shrub.
This plant requires cool soil to grow well. Cover the soil near the stem with organic mulch every year.
Japanese Snowball Watering
The plant must be watered every 7 – 10 days in hot weather. For daily maintenance, just keep the soil slightly moist as too much moisture affects soil porosity, hinders root respiration, causes root rot, and might even kill the plant in severe cases.
Japanese Snowball Humidity
It likes moderately humid conditions.
Japanese Snowball Temperature
Its preferred growing temperature is between 40 – 80 °F. Temperatures above 85 °F will affect growth adversely and temperatures below 40 °F can stunt growth or cause foliar dieback.
It cannot survive tropical summer temperatures. In hot summers, water the plant profusely in the evening, even the leaves.
Japanese Snowball Soil
This plant loves well-draining soil due to its very thin root system; this plant doesn’t handle either waterlogged soil or extreme drought.
A humus-rich, somewhat acidic and well-aerated soil will produce the best growth. Adding perlite will help promote good drainage.
Japanese Snowball Repotting
This plant is fussy about being disturbed once it is established in a container, so the best approach is to plant in large containers with plenty of drainage holes.
The container must be a minimum of 8 inches bigger than the roots, leaving enough space for the roots to expand. This will help the plant to get well established and grow for a few years without needing to be repotted.
When it eventually has to be repotted, early springtime is best as this gives the plant a full year to recover and adjust from transplant shock.
Japanese Snowball Propagation
Propagating this plant from seeds is unwise as it can take around 12 – 18 months for the entire process. Propagation by taking softwood cuttings is the best option to grow new plants. Make sure each cutting possesses 2 nodes for both the underground and aboveground portions.
Prepare individual pots filled with suitable soil and insert the cuttings, making sure 2 nodes are buried and 2 nodes are above the soil.
Water thoroughly and keep the soil slightly moistened until the roots develop – this usually takes 4 weeks. Transfer the new plants to larger containers after new healthy foliar growth begins.
Feed the plant using diluted balanced fertilizer every 2 weeks in spring and summer. Always apply fertilizer when the soil becomes dry and the weather is fine.
After the flowering season ends, prune back the top portion of all the branches every year to dwarf and train the plant into shape. This is particularly necessary for potted plants to control their size. Remove spindly, dead, or diseased branches at any time.
Japanese Snowball Common Problems
Very few pests bother this plant, one of the main reasons it has become popular to grow in landscapes and gardens. Pyrrhalta viburnum or viburnum leaf beetle has become a problem in North America recently and causes a great deal of damage.
The best method to fight these beetles is to encourage predatory insects and remove egg-infested leaves. Some organic pesticides are effective in dealing with this pest.
If the plant is not flowering, look how much light it receives every day — although it can tolerate some shade, plants growing under full sun in temperate climates produce more blooms.
Over-watering might also be a cause, as the plant needs to grow in well-draining soil. Fertilizers that contain too much nitrogen encourage foliar growth but stunt flowering.
High humidity and high temperatures are typically ideal circumstances for powdery mildew to flourish. Usually, plants in shaded areas with inadequate air circulation are more vulnerable to attacks.
It shows as a white powder appearing on leaf margins; then the leaves turn brown, wilt, and drop from the plant. Control it by spraying the plant with a fungicide and avoiding excess humidity and high temperatures.
Leaf spot also occurs easily in conditions of high temperature and humidity. Small yellow-brown blemishes appear on leaves and can spread on all the foliage, causing leaves to become yellow and drop off. It can be controlled and treated with fungicides. Pay attention to air circulation and light during the hot summer months.
How big do Japanese snowball bushes get?
These bushes grow to 10 feet or more when mature and wider. Pruning the plants after they flower will help control their height and width.
Is the Japanese snowball fast-growing?
It can grow between 1 – 2 feet a year.
Where is the best place to plant a snowball bush?
The best spot for the plant to grow is usually under shade in full sun. In temperate climates it can grow under 5 – 6 hours of full sun.
What time of year do you plant snowball bushes?
Depending on the hardiness zone, the best time for planting these shrubs is either in autumn or spring.
How long do Japanese snowballs bloom?
The flowers start blooming in spring and last until early to mid-summer.
Do snowball bushes flower all summer?
The blooms die down in early or mid-summer and then fruits are produced.