Rushmore Arborvitae
Thuja occidentalis 'Rushmore'View more from Arborvitae Trees
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Botanical Name
Thuja occidentalis 'Rushmore'
Outdoor Growing zone
3-7
Mature Height
8
Mature Width
2
Sun needs
Full Sun, Partial Sun
The Rushmore Arborvitae is a selected form of the American arborvitae, hardy to zone 3. It has a slender, elegant form, and it grows to 8 feet tall and just 2 feet wide in ten years. It will ultimately reach 20 feet or more, but still only be 3 to 5 feet wide. It needs no trimming to keep that form, and its swirls of dense foliage look beautiful just as they are. The leaves stay a rich green all winter long, never bronzing or browning, and always looking great in your garden. Grow it as a specimen in a lawn or a bed. Plant a row as a narrow screen for privacy or wind protection. In warmer zones you can also use it as an attractive container plant for a terrace or patio.
Grow the Rushmore Arborvitae in full sun for the best and thickest growth. Plant it in ordinary well-drained soil, and don’t let the soil remain dry for too long, although established plants will easily tolerate ordinary summer dry periods. It is hardy in zones 3 to 7 in the garden, and hardy as a container plant from zone 5. It is not bothered by pests or diseases, although deer will eat it. Use evergreen fertilizer in spring when plants are young, to produce the quickest and healthiest growth. If you want to trim for a more formal look, do this in spring after hard frosts are gone, and again in late summer, if you wish.
Slender, rich green all year, tough as nails, and easy to grow. Everything about the Rushmore Arborvitae is a plus. In colder parts of the country, there is always a need for plants that look green in winter, and this tree is right up there with the best of them. It is more slender and darker in color than Emerald Green, so it is perfect for a rich feature on a lawn, in containers or as a thin but dense hedge. Like the mountain it is named after, this plant will endure, and keep getting better and better.
The Rushmore Arborvitae is an evergreen of moderate growth, reaching 8 feet tall within ten years, but being just 2 feet wide at that time. Ultimately it will exceed 20 feet, and still only be 3 to 5 feet wide, forming a graceful spire soaring into the sky. Imagine it planted among the trees in your yard, or clustered in the corner of your property. The leaves are tiny scales that cling to the branchlets, which in turn are fan-like, and cluster in tight swirls on the branches. Each branchlet lives for several years, by which time it is deep inside the tree, covered by new growth. Only then does it brown and fall, becoming valuable mulch over the root zone of your trees.
As a rich green screen or hedge, the Rushmore Arborvitae has no equal in colder zones, and the dense clusters of tight leaves need no trimming to always look perfect. The branches have a slightly spiraling growth, making for a very interesting profile on plants that are not trimmed too often. Why be out with those trimmers twice a year, when the Rushmore Arborvitae gives you a green curtain with no effort past planting? A green curtain it truly is, with no bronzing in winter, since this is one of the very best arborvitae for rich, deep green foliage all year round. Use it alone or in a cluster of three on a lawn for a striking feature. Plant a row to screen your garden from sight, and from strong winds. Use it inside the garden to separate one area from another. It can also be used in containers, alone or surrounded by other plants, but in a container it is only hardy to zone 5 because the roots of trees are never as hardy as their top growth.
Grow the Rushmore Arborvitae in full sun for the best results and the tightest growth. Plants in shade will always be more open in form and lighter in color, but this plant will grow in partial shade too. It grows best in ordinary soil that is not too dry, and it should be well-drained. It will grow well on damper soils, but not flooded ones, and it is moderately drought resistant once established. It grows well in heavier clay soils, but not so well on dry and sandy ones, where junipers are a better choice. It has no significant pests or diseases likely to cause you any problems, although deer will eat the foliage if they can. For a screen or hedge, space the plants 18 to 24 inches apart, in a row. Trimming is not really needed, but if you want to trim for a smooth, flat surface and a more formal look, then do it in early spring, after the danger of hard frost has passed. Late summer is also a time when you can trim, but don’t do it too late in the year, as new growth might be damaged by harsh winter weather.
The Rushmore Arborvitae is a selected form of the American arborvitae, Thuja occidentalis. Some people know this plant as eastern white cedar. This American native tree is very long lived, and it can be found growing wild all through the north-eastern states, as well as up in south-eastern Canada. Trees can reach 40 to 60 feet in time, and there is no reason to believe that one day, if left alone, your planting of the Rushmore Arborvitae won’t do the same.
South Dakota, the home of Mount Rushmore, is a harsh environment. Most of the state is in zones 3 and 4, with long, hard winters and strong winds. Even the American arborvitae can struggle there, so when Norman Evers, a professor in Horticulture and Forestry at the South Dakota State University, was looking at a batch of seedlings he had grown, it is no wonder one of them caught his eye. With a slender graceful form and rich green leaves all through winter, he knew this tough plant had the right genes for a tough state. If it grew there, it would grow anywhere. He called his plant ‘Rushmore’, and since then it has been grown from stem pieces, genetically identical to that original seedling, to preserve its unique and special features. This plant is not widely available, so we took the stock we found right away, knowing what a great plant it was for colder zones. Order now while our stock lasts, because it will soon be gone.