How to Grow and Care for Doublefile Viburnum Shrubs

The doublefile viburnum (Viburnum plicatum f. tomentosum 'Mariesii') is a medium-sized deciduous shrub (8 to 16 feet in height) that blooms with white flowers from April to May. The dark green leaves on this dense, multi-stemmed shrub are toothed and oval in shape, turning an attractive burgundy red in autumn. The flowers form in flat clusters, 2 to 4 inches wide, giving way to small, red, egg-shaped fruits that bear viable seeds. Doublefile viburnum shrubs have many landscape applications, from single specimen plants to foundation plantings to shrub borders and massed screens. The various viburnum species are the most commonly planted group of shrubs in North America, for good reason: They are extremely easy to grow, with very few problems. Plant them in the fall to enjoy moderate annual growth.

Doublefile Viburnum Shrub Care

Plant this shrub in any well-drained, consistently moist soil for best results. It thrives in full sun but will nicely tolerate some shade. Amending the soil with compost to improve drainage is a good idea in clay soils.

Keep the shrubs consistently moist. Where pruning is necessary to shape the shrubs or control their size, it should be done immediately after flowering. This protects next's year's flowers, as well as the berries, which are much favored by birds.

Light

Grow doublefile viburnum in full sun to part shade locations. Full sun will produce the best flowering.

Soil

This shrub prefers well-drained, loamy, slightly acidic soil but has a wide range of tolerance for most soil types. It does well with other acid-loving plants, such as azaleas and rhododendrons.

Water

Doublefile viburnum likes to be kept consistently moist, though it will tolerate dry conditions once the shrub is mature.

Temperature and Humidity

Viburnum likes moderate climate conditions. It does not do well in intense heat (though will survive if it has some shade and is mulched to keep the soil cool), and it may experience frost damage if a warm winter concludes with bitter cold at the end of the season.

Fertilizer

Like most viburnums, doublefile will appreciate the application of a balanced, time-release fertilizer mixed into the soil in spring. For the amount to use, follow product label instructions. Additional feeding is not necessary.

Types of Viburnum

The viburnum genus includes a great many species. Some good choices include:

• Witherod viburnu(Viburnum cassinoides): This North American native for zones3 to 8reaches 5 to 12 feet in height and width at maturity. Flat-topped clusters of small, white, bad-smelling flowers appear in June in most regions. Fall foliage ranges fromorangeto redtopurple. The edible berries start out green but eventually proceed through shades ofred and blue to a color that is almost black in fall (each berry cluster can contain multiple colors at the same time). The berries persist to provide winter interest as they attract birds
• Golden wayfaring tree (Viburnum var. lantana 'Aureum'): Grow this shrub in zones 3 to 7. Its mature dimensions are 8 feet tall with a similar spread. The flowers and the berries are similar to those on V. cassinoides, but what distinguishes this bush is the foliage color. The new leaves sport an unusualgolden-yellow color thatwill eventually fade to green unless the plant is grown in the shade. The fall color is also yellow.

Doublefile Viburnum vs. Japanese Snowball Bush

A close relative of the doublefile viburnum is the Japanese snowball bush (viburnum plicatum—doublefile viburnum is actually a form of V. plicaturm). The primary difference is that the flowers on snowball bush are round, full "snowball" blooms, rather than the flat clusters found on doublefile viburnum. There are also cultivars of Japanese snowball bush that offer pink or pink and white blooms.

Pruning

Prune this shrub immediately after flowering. Because the shrubs flower on "old wood," pruning immediately after flowering gives them time to develop the growth that will become next spring's old wood. Light pruning can be done at any time, but when rejuvenation is needed every few years, start by eliminating any stems that rub together. Remove a full one-third of all stems, and also remove any water sprouts or suckers at ground level.

Propagating Doublefile Viburnum

Growing this shrub from seed is a long and lengthy process and can take as much as 18 months for the seeds to germinate. It's best to grow these shrubs from cuttings. Like most viburnums, doublefile is fairly easy to propagate by softwood cuttings. Spring through July is the best time to take cuttings, as new growth will be present on the branch tips

1. Cut a 3- to 5-inch segment from the end of a softwood branch, making sure the cutting has at least two pairs of leaves. The cut should be made about 1 inch below the second set of leaves. Peel off the lower two leaves to create wounds from which the roots will grow.
2. Dip the tip of the cutting and the exposed leaf nodes in powdered rooting hormone (the hormone is not absolutely necessary, but will improve the chances of successful rooting).
3. Fill a seedling tray with a good well-drained potting mix containing roughly 60 percent sand or perlite and 40 percent peat moss. (This potting mix can be purchased or made yourself.) Make sure the seedling tray has drainage holes. Plant the cuttings in the seedling mixture, making sure the leaf nodes are completely buried.
4. Water the cuttings until the soil is evenly moist, then place the tray in a large, resealable plastic bag or under a plastic dome. Place the tray in a location with full sun to partial shade, where temperatures stay between 70 and 75 degrees Fahrenheit.
5. After five weeks, check the cuttings for roots; they may be evident through the drainage holes in the bottom of the tray, or you can gently tug on the cuttings to see if there are sufficient roots to keep the cuttings anchored in the soil.
6. When roots are sufficient (this usually takes about four to six weeks), transplant the cuttings into 4-inch pots. Grow the plants until they are about 1 foot tall, then move the plants outdoors.
7. Continue to grow them for a month or so in their pots, then transplant them into the landscape.
   

Overwintering Doublefile Viburnum

Doublefile viburnum shrubs require a bit of care in zones 5 and 6 as they are shallow-rooted plants and can be susceptible to frost. Simply add a layer of mulch around the plant's base, and do not water after the early fall months. If it looks like extreme weather is coming, you can also wrap the plant loosely in burlap to help protect it.

Common Pests

Although the 'Mariesii' cultivaris relatively pest-resistant, it may experience viburnum leaf beetles (Pyrrhalta viburni) and aphids. Spray neem oilon the plant to kill any aphids as soon as you spot them. The leaf beetles are a more serious problem. Control measures should target the larvae, not the adults. The University of Florida Extension suggests biological control, recommending that predaceous insects prefer larvae and adult beetles.

How to Get Doublefile Viburnum to Bloom

These plants like a lot of sunlight, and too much shade can keep them from showing off those beautiful blooms that appear in April and May. Another issue for your viburnum not blooming could be because of the time of year it was trimmed. This shrub flowers on the older mature wood, and if you pruned it before it flowers or too late in the fall, then it doesn't have time to grow the branches needed to produce blooms. Always prune right after the shrub has flowered.

Another cause for viburnum not producing blooms is the fertilizing of the lawn or surrounding areas. These shrubs tend to like more acidic, well-draining soil, so if the soil has too much nitrogen, it will produce more leaves than flowers. Fertilize carefully around any areas that have these types of shrubs.

Common Problems With Doublefile Viburnum

Though there are no serious disease problems with doublefile viburnum shrubs, like other kinds of viburnum, doublefile viburnum can occasionally have problems. Usually, this happens when the plant is not sited in ideal conditions or it is under stress.

Spots on Leaves

Spots on leaves that are black, reddish brown, or pale green, are types of fungus that you should be on the lookout for on your viburnum. These typically can be prevented by not watering with overhead irrigation and keeping the leaves dry. If you do see these spots on any leaves, you can correct the issue by removing those spotted leaves from the plant, raking up around the area to clean up any infected leaves, and controlling the situation with fungicide sprays.

White or Grayish Growth on Leaves

If you notice a white or grayish-colored growth on the surface of leaves, upper and lower, then most likely the viburnum has developed powdery mildew or downy mildew. As with the spots on leaves, do not use overhead irrigation and follow the same procedures; clear up the plants and surrounding areas, and use a chemical spray.

From: thespruce