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Tag: Arborvitae

Why Are My Emerald Green Arborvitae Turning Brown on One Side?

“My Emerald Green arborvitae (Thuja occidentalis ‘Smaragd’) trees were planted by a professional landscaper along the outside of our screened-in porch in February 2019. In the first 3 years, they were lush and full. In the past 2 years, they have lost all of their needles in the side closest to the screen, have become spindly, and show no signs of new growth. What can we do to repair the damage? Have attached 3 photos. HELP!!! Thank you!” Question from George of Milton, Delaware

Answer: Emerald Green arborvitaes are tall, columnar, evergreen shrubs (15 feet by 3-5 feet) that require full sun (6 or more hours a day) on all sides to remain green all around. Sadly, yours have lost all foliage facing the shaded screen due to lack of light, while the sunnier side has maintained foliage. Moreover, based on the photo, it appears they may be competing for light beneath shade trees during part of the day, and the tall shrubs are planted too closely together too close to your porch. Lastly, their tall height prevents you from being about to see outside your porch, if you value your view.

Even with pruning and care, your trees will not develop healthy, green foliage on the shaded porch side, because there simply is not enough light. If the shrubs were moved, they may have a chance, though they are quite large. You might consider replanting shorter evergreens tolerant of shade. I am familiar with Milton, Delaware, and the area around Lewes and Rehoboth.  I recommend planting an attractive shrub tolerant of lower light and the sandy, coastal-plain soils of Sussex County. I’ll recommend some good evergreen and non-evergreen shrub options.

Shrub Recommendations

Look for evergreens tolerant of shade, like tough rhododendrons.

Inkberry (Ilex glabra cultivars). The native shrubby evergreen is tolerant of partial shade, unlike most evergreen hollies. There are many quality varieties available for sale. According to an extensive study at Longwood Gardens, ‘Densa‘ was the best-performing variety trialed. It reaches a mature height of 4-7 feet and is easily pruned. The 5-foot ‘Shamrock‘ is another notable variety to look for, and Proven Winners has introduced several other good inkberries. Give them plenty of water, especially as they are becoming established in the first year.

Azaleas or Rhododendrons may be evergreen or deciduous and quite a few grow beautifully in the area. the evergreen PJM Hybrid Rhododendron (4-6 feet at maturity, Zones 4-7) is a good option with an attractive, rounded habit, lavender-pink flowers that bloom in mid-spring, and evergreen foliage (dark green in summer and reddish in winter). It is tough, reliable, and tolerant of shade.

Hydrangeas provide a good deciduous option with summer flowers. I favor dwarf varieties of oakleaf hydrangea (Hydrangea quercifolia), like Ruby Slippers, or a smooth hydrangea (Hydrangea arborescens) like the tough, 5′ x 5′ Lime Ricky.

Contact the Delaware Center for Horticulture for more good shrub ideas.

Before planting any new shrubs, consider amending your soil with organic matter to fill in the sandy pore spaces and hold water and nutrients. Black Gold® Natural & Organic Garden Compost Blend or peat moss are good, organic options.

Happy gardening,

Jessie Keith

Black Gold Horticulturist

From this angle, it appears there are shade trees quite close to your porch further shading your arborvitae.

Green Screens: Planting for Privacy

Gardeners can create layers of screening plants to create privacy, enclosures, and drama within the garden.

Using plants as screening is the prettiest way to block an unsightly view, demarcate space, channel traffic, or form the walls of an intimate outdoor room. A green screen can be anything from a single eye-stopping specimen to a uniform hedge, to a mixture of evergreen and flowering shrubs, to a vine-adorned fence. The type of plant that does the screening influences the overall personality of a garden as well as the amount of labor required to maintain it.

Ascending Evergreens

Robust, columnar evergreens make a tidy, effective, year-round green screen.

Often, the first plants that spring to mind for screening are three evergreens: Leyland cypress (Cupressus x leylandii, USDA Hardiness Zones 6-9), Japanese cedar (Cryptomeria japonica, Zones 6-8), and arborvitae (Thuja occidentalis, Zones 2-7). Each has a formal aspect and grows at warp speed; Leyland cypress tops out at 75 feet, Japanese cedar at about 50 feet, and arborvitae at 40 feet. Appealing as immediate gratification is, very tall plants can change patterns of light and shade, be difficult to prune, and, worse, grow out of proportion with the rest of a garden. For this reason, gardeners seeking a more manageable evergreen screen have more compact varieties of these trees from which to choose. North Pole® arborvitae has a narrow, conical habit and tops out at 15 feet, and Rein’s Dense Jade Japanese cedar is a choice variety that reaches 25 feet and has very dense growth.

Hedging Plants

Skip laurel has spires of white flowers in mid to late spring and glossy, evergreen leaves.

Another traditional hedge plant is Skip laurel (Prunus laurocerasus ‘Schipkaensis’, Zones 6-9).  It grows moderately fast, is dark green and dense, thrives just about anywhere, tolerates pollution and drought, takes pruning, and reaches about 12 feet. Unfortunately, deer love it.

Deer won’t bother spicily aromatic dwarf bayberry (Myrica cerifera, Zones 7-9), an evergreen that can eventually reach 10 to 15 feet but is generally much shorter. Its loose habit is casual, but for a more formal look, it takes well to shearing. Growing in wet or sandy soils, sun or shade, it isn’t bothered by salt spray or high winds and is ideal for seaside gardens. Northern bayberry (Myrica pensylvanica, Zones 3-7) is equally tolerant of tough growing conditions but is hardier and shorter, reaching between 5 to 10 feet.

Prague viburnum is an evergreen spring bloomer with a less formal appearance when used as a screening shrub.

A uniform clipped hedge is at home in a formal garden. Informal gardens allow for looser, more textured shrubs, such as the deep evergreen Prague viburnum (Viburnum x pragense, Zones 5-8).  It will reach 8 feet tall by 6 feet wide quickly in the sun or part shade.  It grows in full shade but won’t produce the fragrant, creamy white May flowers that are followed by showy black berries. The equally informal All that Glows® Arrowwood (Viburnum dentatum) is a pleasing deciduous viburnum that is tough and creates a fine screen. It takes well to shearing, has glossy leaves, and white flower clusters in late spring followed by clusters of deep blue berries that remain attractive into fall.

Screening Grasses

Feather Reed Grass has a stark upright habit and creates a fine green screen from summer through winter.

Informal gardens also allow for out-of-the-box thinking.  How about a screen of ornamental grasses?  Drought-tolerant, deer-resistant switchgrass (Panicum virgatum) is a tall, airy, native and some cultivars can reach up to 6 feet or more. The award-winning ‘Northwind’ (Panicum virgatum ‘Northwind,’ Zones 4-9) is vertical with olive-green blades and soft panicles that top out at 6 feet. It grows quickly in a single season. Another grass with a vertical appeal is the classic Karl Foerster Feather Reed Grass (Calamagrostis x acutiflora ‘Karl Foerster’), which reaches 4 to 6 feet. It’s upright green panicles age to warm tan by fall and remain attractive through winter.

Or how about grasses and shrubs in combination? Deer-resistant blue fountain or clumping bamboo (Fargesia nitida, Zones 5-8) reaches 10 feet tall or more.  Clumps are dense, but the thin. Erect canes have a linear appearance that contrasts handsomely with bold, broadleaf evergreens in the foreground, such as Beale’s mahonia (Mahonia bealei, Zones 6-9)–a deep green shrub with prickly evergreen leaves that grows up to 10 feet tall and nearly as wide. Another complement would be Oregon grape holly (Mahonia aquifolium, Zones 6-8), which grows to 6 feet or slightly more and spreads to 5 feet wide. Fragrant yellow flowers bloom in the earliest spring. (Click here to read more about Oregon grape holly.)

Mixed Screens

Mixed screens, comprised of varied plant material and media, provide continuous appeal.

Alone, evergreen Sky Pencil holly (Ilex crenata ‘Sky Pencil’, Zones 5-8) is ideal for a medium green screen in a narrow area.  It reaches 10 feet, but stays 3 feet wide and under, grows in the sun or shade, isn’t fussy about soil, and needs no trimming. It is sensational when alternated in a hedge with just about any shorter flowering shrub. One choice might be deciduous flowering quince (Chaenomeles speciosa, Zones 5-8).  Quince grows to about 6’ tall and bears pink, red, or white early-spring flowers, followed by tart fruits that can be used in jams and jellies. Its thorns deter deer, but there is a thornless and fruitless variety called Double Take Orange™ ( aka. Double Take Orange Storm), which has double flowers of deepest orange that make it well worth growing.

Privatizing Climbers for Fences

Sometimes a well-espaliered tree, like this apple, makes its own green screen.

Sometimes, for reasons of space and time, only a fence will do.  Espaliered trees or shrubs like apples, pyracantha, and camellias (Camellia species, zones 7-9), or a woody vine, like climbing hydrangea (Hydrangea anomala subsp. petiolaris, Zones 5-9), are great choices for added fence or green wall screening that goes a long way to improving the view.