Doublefile Viburnum Viburnum plicatum f. tomentosum 'Rowallane'

Water

The Doublefile Viburnum requires consistent moisture, especially in the first few growing seasons. Water deeply once a week, applying about 1.5 gallons per watering to thoroughly soak the root zone. During periods of drought or extreme heat, the frequency may need to increase to twice a week to maintain soil moisture. Avoid shallow sprinkling, as it encourages weak root development. Always check the top few inches of soil for dryness before watering to ensure the plant is not overwatered.

Light

The Doublefile Viburnum thrives in full sun to partial shade. The ideal location is one where the plant receives at least 4 hours of direct sunlight each day, with some afternoon shade to protect from the intense late-day sun. A spot with dappled sunlight or morning sun with late afternoon shade is also suitable for healthy growth and flowering.

Temperature

The Doublefile Viburnum can tolerate a range of temperatures and is hardy from USDA zones 5 through 8. It can withstand minimum temperatures down to -20°F and maximum temperatures up to 90°F. The ideal temperature for promoting growth and flowering is between 60°F and 80°F.

Pruning

Prune the Doublefile Viburnum immediately after flowering to maintain its shape and encourage healthy growth. Cut back the branches that have just flowered to a point of strong, outward-facing buds to stimulate new growth and flower production. Pruning is typically required once a year, but light trimming to remove dead or broken branches can be done as needed throughout the year.

Cleaning

As needed

Soil

Japanese Snowball (Viburnum plicatum f. tomentosum 'Rowallane') thrives in moist, well-drained soil that's rich in organic matter with a pH range of 5.5 to 6.5. For optimal growth, mix garden soil with compost or peat moss to enhance fertility and water retention. Regular mulching will help maintain soil moisture and temperature.

Repotting

Japanese Snowball doesn't typically require frequent repotting if planted in the ground. For container-grown specimens, repot every 3-5 years or when roots outgrow the pot, usually in late winter or early spring before new growth begins.

Humidity & Misting

Japanese Snowball prefers moderate humidity levels but is generally tolerant to the varying humidity conditions found in most outdoor environments. It does not have specific humidity requirements when grown in its ideal outdoor setting.

Suitable locations

• Indoor

  Not ideal for indoor growth, needs sunlight.

• Outdoor

  Plant in partial shade, moist soil, mulch yearly.

• Hardiness zone

  5-8 USDA

Life cycle

The life of Viburnum plicatum f. tomentosum 'Rowallane', commonly known as Doublefile Viburnum, begins with seed germination, typically in spring to early summer, in well-drained soil with adequate moisture. Seedlings emerge and grow into juvenile plants, developing a strong root system and the characteristic horizontally tiered branches. The plant enters its vegetative stage, producing dense, green foliage, and as it matures, it begins the reproductive stage, blooming in late spring with showy, lace-cap flowers attractive to pollinators. Following pollination, the flowers give way to red berry-like drupes that mature to black, providing food for birds and completing the reproductive cycle. The plant then enters a period of dormancy during the winter months, conserving energy for the next growing season. Across years, the plant continues to grow in size and spread, potentially reaching up to 10 feet tall and wide, with the cycle of flowering and seed production occurring annually.

Propogation

• Propogation time

  Spring-Early Summer

• The most popular method of propagating the Japanese Snowball, scientifically named Viburnum plicatum f. tomentosum 'Rowallane', is through softwood cuttings. This technique is often carried out in the late spring or early summer when new growth is still tender and green. To propagate, one should cut a 4 to 6-inch (10 to 15 centimeters) length of stem from a healthy part of the plant, ensuring there are a couple of leaves on the cutting. After removing the leaves from the lower half, the cut end can be dipped into a rooting hormone to encourage root growth. The treated cutting is then placed into a well-draining potting mix, with good moisture, and kept under indirect light until roots develop, which typically takes several weeks. Maintaining a humid environment by covering the cutting with a plastic bag can help improve the chances of successful rooting.