How to Plant, Grow, and Care For Distylium Shrubs

While years in the making, Distylium hybrids are relatively young on the ornamental scene, with new varieties entering the market in exciting forms and variegations. Depending on the selection, the attractive evergreens have graceful scaffolding or upright branches and narrow, lustrous leaves in deep olive to blue-green.

In addition to their pleasing stature is their ease of growth. These exceptionally low-maintenance shrubs thrive across hot, humid climates and have good cold tolerance while requiring few additional resources and little gardener intervention. With no real problems to speak of, the merits of these handsome specimens speak for themselves in the landscape.

What is Distylium?

Distylium, also Isu tree or winter hazel, is a versatile, no-fuss evergreen for warm climates. There are 18 species occurring in Asia, with two in cultivation. Increasingly popular in the home garden are hybrids originating from these two species, D. racemosum and D. myricoides. Dr. Michael Dirr at the University of Georgia and colleagues at Plant Introductions, Inc. are largely responsible for the initial hybrids, which remain top performers, with more in their company and still others in the works. 

The architectural plants are pest-free and grow in coastal and high-heat conditions. They’re also disease-resistant, drought-tolerant, and need little to no pruning. Some selections grow well across moist conditions.

The durable evergreens make suitable stand-ins for Indian hawthorne, laurels, boxwoods, nandinas, and hollies that may suffer insect and disease problems. They complement a mixed screen or standalone as a hedge, foundation, or mass planting. They’re a fit for formal and informal styles alike.

The low-maintenance, easy growers are free of severe problems. Even deer and rabbits usually don’t bother them. This a stable, attractive, carefree perennial shrub with multiseason appeal.

Characteristics

Distylium bears glossy, dark olive to blue-green leaves held upright on scaffolding stems. While dense with ample foliage, the long, slightly arching stems give a graceful look. New growth emerges in copper, red, and purple, depending on the variety.

Inconspicuous red blooms dot stems in late winter and early spring, usually January through March. Small brown seed capsules follow, with no messy drop or aggressive spreading.

Form and growth habit vary by selection, but they share a compact nature and fine texture. Whether low and spreading or upright and columnar, there’s a variety for any number of garden situations.

Native Area

Distylium is in the witchhazel family (Hamamelidaceae). D. racemosum (isu tree) and D. myricoides (blue isu tree) are the parent trees to the cultivated shrubs and are native to China and Japan. D.racemosum brings rugged growth to the mix. The small tree (quite large in the wild – up to 60 feet) is hardy to zone 6. It’s heat and drought-tolerant and grows in sun or moderate shade free of pests and diseases. D. myricoides enhances the aesthetics with layered branches and linear blue-green leaves.

D. racemosum occurs at elevations of 3,000 to 4,000 feet, while D. myricoides grows at 1,000 to 2,000 feet and is less cold hardy (zone 7). They grow in forested sites and benefit from protection from winter winds.

Planting

At planting, dig a hole twice the size of the nursery pot and loosen the surrounding soil. Gently remove the shrub from its container, noting that the bulk of the roots may lie at the bottom of the pot as they sought moist conditions while growing.

Depending on the variety, spacing varies from about two to four feet apart to allow room for mature spread. The specimens are slow growers and easily pruned, but they look best showing off their natural form with some overlapping.

Transplanting 

Fall and spring are the best times for planting. Cool temperatures and seasonal moisture give roots time to establish before winter and summer temperature fluctuations. For the least stress, avoid planting in frozen or waterlogged conditions and extreme heat or dryness.

How to Grow

The carefree, easy growers have low maintenance needs. Even so, certain cultural requirements, like regular moisture and sun exposure, are best for optimal health.

Light

The evergreen shrubs grow best in full sun (with six or more hours of sunlight daily) to partial shade (four or more hours). Branching takes on a looser habit in the shade than in the sun.

Water

The adaptable growers do best with consistent moisture, though they tolerate periods of drought once established. They also withstand periodic saturation and perform well in rain gardens.

About an inch of water per week is sufficient, with only supplemental irrigation needed during dry spells after the first two growing seasons. Water through frost to prepare them for winter.

Soil

Distylium tolerates various soil types, including clay, but does best in average, medium, and well-drained soils. While not finicky about soil pH levels, slightly acidic is optimal.

In poor soils like clay and sand, add compost at planting. Compost improves aeration, moisture retention, drainage, and nutrition. Adding a compost layer to the garden bed or container each spring refreshes these benefits for the growing season.

Temperature and Humidity

The shrubs are heat and humidity-tolerant, given good air circulation and moist but not overly saturated soils. They perform across the southeast with no summer issues.

Cold hardy down to USDA zone 7 (and sometimes 6), they benefit from extra mulch and protection from winter winds in the lowest zones. New, tender spring growth may be susceptible to late frosts.

Fertilizing

With nutrient-rich soils, the hearty specimens don’t require additional fertilizers to thrive. They’ll benefit from fresh compost each spring. If you opt to fertilize or have poor soils, apply a balanced, organic, slow-release, like 5-5-5, at planting and in early spring.

Maintenance

Distyliums are truly low maintenance. No pruning is necessary, but if you want to do some snipping, remove the tips post-flowering in late May or June to promote a bushy, compact form. They take shaping well if you’re forming a uniform hedge or screen, but their natural, graceful form doesn’t warrant cutting.

For added temperature regulation and moisture retention, add a layer of mulch around the plants. Keep it off of the stems to prevent rot and other crown diseases.

Propagation

Plant patents protect commercially-grown hybrids and prohibit propagation. Source these from your local nursery. Straight species (D. racemosaum and D. myricoides) propagate via seeds and cuttings.

Take soft stem cuttings in early summer. Collect seeds in the fall for fresh sowing or for cold stratification over the winter.

Cuttings

Growing From Seed

Collect seed capsules as they brown in the fall and place them in a paper bag for a few days until the capsules expel the seeds. Direct sow the fresh seeds in a prepped garden area or tray, covering them lightly with soil.

Dried seeds require cold and moist stratification to germinate. Refrigerate or direct sow them in late fall or winter for two to three months of cold exposure.

Popular Varieties

Hybrids offer exciting forms, sizes, and foliage colorations to fit various spaces and styles. The reliable performers offer all-season visual interest and textural contrast.

‘Vintage Jade’

‘Vintage Jade’ is one of the best-known and most compact varieties. Growing three feet tall and four feet wide, it’s ideal as a foundation planting, along walkways and borders, and on slopes. 

‘Vintage Jade’ has a mounding habit and dark green, glossy leaves. Tiny red blossoms line stems in February and March. This is the first patented selection and remains a favorite.

‘Linebacker’

‘Linebacker’ is unique as the tallest among the hybrids. The dense, upright grower reaches eight to ten feet tall by six to eight feet wide – a statuesque player good for hedging, even if it doesn’t grow as large as advertised.

‘Linebacker’s’ new growth emerges in tinged in red and matures to deep green.

‘Cinnamon Girl’

‘Cinnamon Girl’ is a low-grower with a refined look ideal for the border. She reaches two to three feet tall and four to six feet wide. 

The real draw is the new growth when small, purple-red leaves swirl on graceful, arching branches. ‘Cinnamon Girl’ is among the more cold-tolerant cultivars, with hardiness to zone 6.

‘Blue Cascade’

A compact spreader with layered stems and long, blue-green leaves, ‘Blue Cascade’ lives up to its name with a flowing form. New leaves emerge purple-bronze.

‘Blue Cascade’ is versatile at three to four feet high and wide and is hardy to zone 6.

‘Coppertone’

‘Coppertone’ adds spice with coppery red new growth. Leaves mature to blue-green with purple tones in winter.

The mid-sized variety has a rounded growth habit and grows three to four feet high and four to five feet wide. Slightly stiffer stems hold upright leaves.

Common Problems

While maintenance-free, Distylium is also free of most pests and diseases. Maintaining optimal growing conditions promotes vigorous specimens with the greatest resistance.

Fungal root rot can occur in overwatered situations. Root rot causes plants to decline due to an inability to absorb water and nutrients. The pathogen Phytophthora impacts feeder roots, preventing them from uptaking water and nutrients. Leaves appear drought-stressed, turn yellow, and wilt.

Look for rot slightly below the soil level. If rot is the problem, the stems will be yellow, and the roots will be brown and mushy rather than a healthy white.

If caught early and with only minor damage, the shrub can recover. Reduce irrigation frequencies to allow oversaturated soils time to drain. Keep soil evenly moist but not soggy. 

Proper cultural management, especially not overwatering, is the best control. Water deeply and increase the length of time between sessions if needed. Deep watering allows better absorption over frequent, shallow watering. Distylium does well with drying out slightly between sessions. Allow plenty of airflow between plants and surrounding structures.