Thuja occidentalis 'Sienna Sunset'
Miniature Eastern Arborvitae
Thuja occidentalis 'Sienna Sunset' (aka ANNIEK) (PP22,813) - A dense bowling ball-shaped conifer, a miniature Eastern Arborvitae. New foliage is bright acid green in spring and very soft to the touch. The color settles back to a deep green in summer. Late season when temperatures grow colder and days grow shorter the foliage colors to amber and orange. It's fantastic. A good foundation plant 'Sienna Sunset' will be at home in the rock garden, a railroad garden, in a knot garden or even a repeated component in a formal garden. Fertile, moisture retaining soil in part to full sun. Avoid lime. Established potted shrub, cutting grown. Please read the Genus Overview below.
Zone:5 to 7
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Characteristics and Attributes for Thuja occidentalis 'Sienna Sunset'
Season of Interest (Foliage)
- Four Seasons
- Morning Sun / Afternoon Shade
- Mostly Sunny
- Full Sun
- Formal Garden
- Knot Garden
- Rock Garden
- Small / Miniature
- Railroad Garden
Growth Rate in the Garden
- Garden Origin
Genus Overview: Conifers
Conifers. This exceptionally diverse group includes mostly evergreens exhibiting all manner of size, color and shape cloaked in scale-like foliage as in Arbor vitae (Thuja) and Elkhorn Cypress (Thujopsis) and Junipers (Juniperus) generally to the needled species like Pine (Pinus) and Spruce (Picea). Some notable deciduous members include Larches (Larix), Bald Cypress (Taxodium), Dawn Redwood (Metasequoia) and Golden Larch (Pseudolarix). There is much vexing confusion for customers surrounding eventual sizes of these remarkably diverse cone-bearing plants which range from shrubby mat-forming members to majestic, gigantic trees with a roster of shapes and forms between.
The American Conifer Society has developed a size classification system which, though imperfect, is nevertheless a helpful aid to customers who understand it and know how to apply it to a potential purchase. This classification system projects the rate of growth in a 10-year span and not the ultimate adult size of a plant. The system is as follows:
Miniature: up to 1 inch per year. Estimated size in 10 years is up to 1 foot.
Dwarf: average rate of 1+ to 6 inches per year. Estimated size in 10 years is 1+ to 6 feet.
Intermediate: average rate of 6 to 12 inches per year. Estimated size in 10 years is 6 to 12 feet.
Large: average rate of 12 or more inches per year. Estimated size in 10 years is 12 feet or more.
Often, when a customer sees a label that says that a form is “dwarf” it is assumed that this plant will remain small. It is relevant that the potential buyer knows how big the straight species will grow. A dwarf plant may eventually grow large... it just may take a longer period of time to get there. For instance, Dawn Redwood (Metasequoia glyptostroboides) can grow to monumental proportions – up to 120 feet in ideal conditions. A dwarf form of Dawn Redwood means that this particular form will exhibit a slower growth rate in relation to the straight species. A dwarf form of Dawn Redwood could still attain stratospheric heights; it could just take longer to get there. But this is entirely dependent entirely upon the form's genetics.
Specifically, Metasequoia glyptostroboides 'Ogon' is a gold-needled form of Dawn Redwood. Its genetics make it a slower grower. But though it may top off at a lower height than its green brother, in that the green species can reach 120 feet tall the somewhat less rambunctious golden sibling could stretch to 70 feet in time, perhaps taller. Slower and potentially smaller as an adult tree 'Ogon' will eventually grow to be a big boy. So, again, I have to stress it is crucial to know how big the straight species will grow. It is fundamental to understand that what is often assumed to be a plant size designation as exemplified by “miniature, dwarf, intermediate and large” in reality refers to growth rate, not necessarily ultimate size.
Another problem with this system is that many conifers are slower growing when new or recently planted. They remain smaller with a commensurate slow growth rate when initially interred. It takes some years for them to make substantial root and top growth at which point they may grow at a faster rate. Also, some cultivars when they reach a certain mass eventually pick up an almost exponential growth rate. It is not uncommon for some dwarf shrubs to eventually jump the dwarf designation into the intermediate growth category, from 1 to 6 inches per year to 6 to 12 inches per year or from the intermediate category to the large, from 6 to 12 inches per year to 12+ inches per year.
Conifers again, are a large and very diverse group in the greater plant kingdom. Any classification system that attempts to pigeonhole the enormous volume of forms and cultivars in any given species among the many genera of conifers may be helpful but will be imperfect. Know the species. Understand how the size rating categories work, employ them with understanding and you will make wiser, long term decisions.
Junipers tend to settle in fairly fast but many / most of our other offerings take longer periods of time – up to 3 years. In the case of Sciadopitys, which are painfully slow as small plants, at least 3 years and often longer is a safer bet.
Of utmost importance: be sure to water all conifers during hot, dry spells through the first couple of summers at least. And if a dry autumn follows provide extra deep waterings as well. Often, a wind screen made of burlap attached to stakes surrounding your purchase is very helpful in the first winter. Junipers may not require protection the first winter unless at the very fringes of their northern range. Organic mulches of wood chips and / or leaves are important – perhaps less important to Juniperus though helpful nonetheless. I hope this has been helpful.