Thunderhead Japanese Black Pine

'Thunderhead' Japanese Black Pine at U.T. Gardens in Knoxville

Thunderhead (Pinus thunbergiana) is a choice shrub variety of Japanese Black pine. This medium-sized evergreen shrub conifer grows 10 to 12 feet high and 12 to 15 feet wide (in 10 - 15 years). Its distinctive cottony terminal buds and dark green densely packed needles are architecturally beautiful in the fall-winter landscape.

“Billowy emerald clouds” best describes the needle foliage on Thunderhead pine.  Silvery white candles (shoots) grow 10 - 12 inches long in response to warm spring temps.  The shoots reach their full length by late May. Branches are rigid and its lower needles are mostly retained.

Desired location is in full to partial sun and in moderately acidic soils that are well-drained. Provide a minimum of 6 hours of sunlight. Plant in late winter to early fall from container or balled and burlapped (B&B) stock. Allow 1-2 years to become established after planting; afterwards drought and heat tolerant.

Feed annually in late winter with 10-10-10 or equivalent granular fertilizer. Pruning is rarely necessary except for desired shaping and sizing. Cut back new shoot growth (“candles”) around late May to early June before needles are fully expanded.

Disease and pest problems are rare when properly sited. Thunderhead is highly tolerant of wind, drought, and salt spray. Provide shelter from harsh winds to minimize off-color in winter. Availability is primarily from specialty conifer nurseries on-line or in the southeast region.

Thunderhead Japanese black pine is loved for its low maintenance and its dark evergreen foliage. This shrub pine conifer deserves a place in your landscape.

Vertical Accents Using Boxwoods And Japanese Hollies

'Sky Pencil' Japanese Holly

Boxwoods and hollies are popular landscape evergreen shrubs (USDA hardiness zones 5-8). Both are utilized for low hedging and privacy fencing and some varieties are planted for their architectural accent.  Both shrub groups grow best in moist, slightly acidic, well-drained soil and in full sun to partial shade.

These shrubs are regularly pruned and shearing. Spring pruning should be avoided as it tend to stimulate tender new growth that may be injured or killed by late frosts.

In general, boxwoods tend to be more shade tolerant than hollies. Boxwood is best sited where it is sheltered from strong winds, and protected from full day sun in the winter months. Foliage may also bronze in winter. Carefully remove heavy snow accumulations as quickly as practicable to minimize stem/branch damage ("splaying").

'Dee Runk' boxwood

There are few shrubs that fit into narrow spaces better than 'Dee Runk' boxwood (Buxus sempervirens 'Dee Runk'. It is a better choice than currently popular cultivar 'Graham Blandy', which is seriously troubled by soil root rot diseases, particularly Phytophthora.

'Sky Pencil' Japanese holly (Ilex crenata 'Sky Pencil') exhibits a similar upright (fastigiate) form. Japanese holly demands a well-drained soil, and is very susceptible to several soil root rot diseases including Phytophthora and Pythium.

Both 'Dee Runk' boxwood and 'Sky Pencil' holly grow well in large landscape containers on patios and along downtown streets. Expect mature heights between 8-10 feet.

Aucuba -- the "Holly" of the Shade Garden

On a recent trip to the Knoxville Botanical Garden, I was re-introduced to a shrub, not used as much as it should be - gold dust plant (Aucuba japonica). Hardy to garden zones 6b-10, aucuba is at home in part sun to heavily shaded areas in the garden. Direct sunlight, even in the darker winter season, will scorch the foliage.
I've enjoyed a "plain green" foliage variety in my landscape over the past 16 years. It is tucked among three Japanese maples. Its holly-like leaves and bright red berries (on female cultivars)become more noticeable after the surrounding maples have surrender their fall plumage.

Many gold leaf cultivars sparkle in an otherwise dreary winter garden. Many cultivars abound. I particularly like 'Picturata', exhibiting large bright golden splotches in the center of each leaf and splashed by tinier yellow specks.

Branches on this 8-10 foot tall shrub are upright in habit. Growing culture is the same as hollies - preferring a well-drained, richly composted and moist soil site.