Marianne Ophardt

Dwarf plants can grow bigger than you expect

When someone tells you a plant is a dwarf, it really doesn't tell you much.

When it comes to trees or shrubs, the non-dwarf "normal" plant may grow 20 feet tall or more and the "dwarf" may grow to "only" half that size ... 10 feet. That's probably not the compact, little well-behaved dwarf plant that you expected.

One such plant that grows much beyond many gardeners' expectations is the burning bush or winged euonymus (Euonymus alatus). The species is a large-sized shrub known for its bright red fall coloring. It grows very slowly but can reach both a height and width of 15 feet. The cultivar typically referred to as a dwarf burning bush (Euonymus alatus Compacta) is also slow to grow to its full potential height of 8 feet tall and wide -- not really a petite shrub.

There are other cultivars that are smaller than this common "dwarf" cultivar. "Little Moses" is the diminutive size you might expect from a dwarf burning bush. It grows to a height of only 3 to 4 feet and forms a shrubby mound with no bare stems at the base. The fall foliage is bright red.

Another "dwarf" shrub that often eventually far exceeds the space it was provided is dwarf mugo pine (Pinus mugo var. mugo). It is relatively small, growing only to a height of 8 feet and a width of 16 feet compared to the species that can grow to 20 to 50 feet tall! Pinus mugo var. pumilio is another dwarf that grows only several feet tall but is more open and sprawling to a width of 10 feet.

If a small size is the goal, other cultivars are definitely smaller. "Mops" is a tightly compact mugo pine reaching only 3 feet in height and "Slowmound" is a dark green form that also grows only 3 feet tall. For an itty-bitty mugo pine, search for "Teeny." It grows so slowly that over a span of 10 years it may only reach a height of 12 inches.

The species form of the border forsythia (Forsythia intermedia) grows to a gangly 8 to 10 feet tall and 10 to 12 feet wide. The only time of year that it's truly attractive is at this time of year when it's in full bloom and covered with bright yellow flowers. When you plant this, you're committing to regular pruning to keep it contained.

There are a number of different dwarf border forsythia cultivars that should be planted in the typical home landscape instead of the rangy species. These include "Gold Tide" a 2-foot-tall shrub with lemon yellow flowers; "Golden Peep" a golden-flowered mounded shrub growing to only 30 inches tall; "Goldilocks," a 2- to 3-foot mounded shrub with bright yellow flowers, and "Arnold Dwarf," which grows to a maximum of 3 feet tall and 7 feet wide.

Most gardeners wouldn't consider placing a full-sized red elder bush in their landscape, since it can reach a height of 12 feet and doesn't really have any outstanding ornamental characteristics. However, the dwarf red elder might be considered. "Golden Locks" grows to 3 to 6 feet tall and has attractive dissected golden leaves, which contrast well with its small round red fruit. It will probably perform best in this region when placed in a protected spot with partial shade.

One shrub I particularly like is the dwarf blue leaf arctic willow (Salix purpurea Nana) It's fine-textured with narrow stems and blue-green foliage. It develops into a compact mounded shrub without pruning. Its graceful swaying in the wind along with its delicate texture make it an interesting addition to the landscape. It's a fast grower and will tolerate poor soil and some drought. As a dwarf, it grows from 4 to 6 feet in height. (The species grows 10 to 12 feet tall.)

Despite being a lovely plant, I'm not sure how many people will plant the European cranberrybush viburnum (Viburnum opulus) since it grows to a height of 10 feet and a width of 10 to 15 feet. A multistemmed shrub with a rounded shape, it's valued for its dense, compact form, maple-shaped leaves that turn reddish purple to yellow-red in the fall, and attractive flat-topped clusters of white flowers. The shrub blooms in late spring to early summer and is showy when in bloom. An added bonus are the clusters of bright red fruit that persist from late summer into fall.

There are several dwarf forms of the European cranberrybush viburnum that fit a little easier into a home landscape. "Leonard's Dwarf" grows to 4 feet tall and produces abundant flowers and fruit. "Bailey Compact" grows to 6 feet tall and its leaves have a deep red fall color. "Compactum" grows to 5 feet tall with a dense, compact habit. "Nanum" grows only 2 feet tall but doesn't produce many flowers or fruit.

So "dwarf" is a relative term. If a plant is labeled as a dwarf, check its tags and consult references to find out just how big it may grow when it reaches maturity. Cute little plants often become much larger than expected even if they're called a dwarf.

* Marianne C. Ophardt is a horticulturist for the Washington State University Extension Office in Benton County.

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