Dwarf Conifer Confusions
Almost every retail garden center will have an area for dwarf conifers. However, almost every one of them will have a different concept as to just what a dwarf conifer actually is. All too often a person will go the local garden center looking for a dwarf conifer to fit into his landscape and leave with a dwarf mugo pine ( Pinus mugo v. pumilio ), a dwarf alberta spruce ( Picea glauca 'Conica' ), or a dwarf blue spruce ( Picea pungens 'R. H. Montgomery' ). Along with the plant the customer takes the assurance that they have purchased a dwarf conifer.
Pinus mugo v. pumilio, a.k.a. dwarf mugo pine, is nothing more than a variety of mugo pine grown from seed that grows slower than most of the other mugo varieties. Since it soon becomes a one to two meter ( 3-6 feet ) wide globe, it hardly qualifies as a dwarf. If the consumer buys several of them for a formal setting where they all have to be identical, he has made a poor choice. Since these mugos come from seed, they not only all grow a little bit differently, they will also exhibit varying shades of green.
I remember visiting a large wholesale nursery in Oregon one summer and seeing a crop of 10,000 mugo pines in 5 gallon containers. The plants were identical in shape, (due to regular shearing), but exhibited a thousand different shades of green foliage. If a person wants to purchase an honestly dwarf mugo pine, he must select a named variety. The name will belong to a plant that always grows in the same manner and will have a published description. Of course, the consumer should purchase the plant from a reputable nursery because often plant factories wil have unskilled laborers who mix up labels.
Picea glauca 'Conica', a.k.a. dwarf Alberta spruce, grows into an ultra dense, conical tree that is just what everyone pictures as a Christmas tree. Unfortunately it will eventually reach a height of two to three meters ( 3-6 feet ). That is dwarfer than the species, Picea glauca, but it is questionable if it can actually be considered a dwarf tree, especially since plants grown in the Northwest will often be fertilized and watered into a growth rate of almost 20 centimeters (8 inches) per year.
Then too, rare is the nursery that will mention the word spider mite around this plant. 'Conica' was a common plant in landscapes in the 1940's and 1950's throughout much of America. However, it suddenly became very rare. Its overuse led to a plague of red spider mites that destroyed or disfigured plants throughout the country. It was "rediscovered" in the seventies and is once again becoming very common. In fact, one nursery in Oregon was producing 300,000 'Conica's a year in various sizes for the wholesale nursery trade. They, however, were not the biggest producer in the state.
Picea pungens 'R. H. Montgomery', a.k.a. dwarf or 'Globosa' blue spruce, is a very popular plant in the Northwest nursery trade. Many thousands are sold every year in garden centers as dwarf conifers. Unfortunately they are not dwarf. The selection named 'Globosa' will eventually grow into a conical shape because it is actually a conical plant named 'R. H. Montgomery'. Why the confusion? Side shoots propagated from 'R. H. Montgomery' will tend to develop into globose plants when young and have great appeal to the consumer. However, 'R. H. Montgomery' grows up to 25 centimeters (ten inches) per year and can become very broad. A consumer who puts this plant within one meter (3 feet) of his house foundation will have to remove it within ten years.
So how does a consumer manage to obtain true dwarf conifers? People in the Seattle/Portland corridor can visit me for older plants. Anyone can order younger plants for shipment. Otherwise, a person has to explore real garden centers, not the local discount centers. Plants may cost more at garden centers, but the consumer is much more likely to get service from a person who knows something about what he is selling. Look for plants that have cultivar names and have good, understandable descriptions about those cultivars.
A cultivar name is the name inside the single quotes that follows the scientific name. For example, Pinus mugo 'Valley Cushion' is the full name of a truly dwarf mugo pine. Pinus mugo is the scientific name. 'Valley Cushion' is the cultivar name. This cultivar name belongs to a selected seedling of mugo pine that grows according to a published description. All 'Valley Cushion' plants originated from a single seedling, and they all grow identically to it.
It is not easy to find dwarf conifers of any size for obvious reasons. Dwarf conifers grow slower so they are expensive to produce by the nurseryman. Since most people want to buy cheap plants, nurseries tend to grow plants that are of a landscape size within three years. The consumer who buys this cheaper plant doesn't realize that the growth will not magically slow down once he puts it into his landscape. Typically, in a few years it will outgrow its place and must be removed. Then the whole cycle repeats itself.
A dwarf conifer will be more expensive but if it is a true dwarf conifer, it can stay in its home for as long as twenty years or more. In the long run, such a plant not only costs less, but it also means the landscape is much more permanent.
All of this discussion leads me to a definition of a dwarf conifer. Ten different people will have ten different definitions. My own goes like this: "A dwarf conifer will not attain a size of more than two meters (six feet) in any one direction within twenty years of normal growth. Normal growth being defined as how it would grow in its native range and soil without any special treatment." Any plant can exhibit an abnormal growth rate if it is heavily fertilized and watered in a milder climate. The Portland, Oregon area does not have its many nurseries by accident. Plants grow faster there.
If a conifer is extremely dwarf, it can be referred to as miniature. A miniature conifer will be smaller than one meter (three feet) at twenty years under these same conditions.
If other people want to use different definitions, that is all well and good. But be certain to know those different definitions, especially as they apply to plants you may wish to buy.
Counter Started March 31, 2002