Dwarf Alberta Spruce, Picea glauca ‘Conica’
Foliage: Small green needles; evergreen
Height: About 12 feet in many years; grows about 3 inches per year
Spread: About 5 feet in many years
Main features: Dwarf Alberta Spruce is quite common in the garden center trade. It is a slow- growing densely compact conical conifer with a formal look due to its dense symmetrical form. This cultivar is useful in a dwarf conifer garden, as a foundation plant, used on either side of a landscape element (e.g., entryway, art work, sign) to frame that element, as a short hedge, in a container (at least for several years before it gets too big), as a focal point, or as an accent plant. The height of this plant is commonly stated as 5 feet but this is somewhat misleading since it will ultimately be taller than 10 feet, but this would take about 50 years or so. Under good conditions the plant will grow about 3 inches per year, so to calculate the ultimate size in your lifetime, multiply 3 inches by the number of years you expect to be with the plant. This will also dictate where to site the plant in your landscape (to avoid cutting down the plant due to the plant impinging on an adjacent space/structure). Dwarf Alberta spruce has two potential problems: 1) occasionally, the plant reverts to the species form (white spruce, Picea glauca; a medium/large tree with distinctly different foliage), and 2) it is prone to mite infestations. In the case of reversion, part of dwarf Alberta spruce will produce a vigorous shoot that is unlike the rest of the plant. What has happened is that the genetic switch for dwarfism (the typical dwarf Alberta spruce type) for some reason was turned off and the genetic switch for the species characteristics (bluish foliage, much faster growing, tree form) was turned on. If one notices atypical growth on a dwarf Alberta spruce, then they must prune it out of the plant. If one waits too long to remove that branch, it will produce a large branch that will not only shade out the typical dwarf growth habit, but removing a large branch will leave a large unsightly gap in the foliage which will take a long time to fill. In the case of a mite infestation (small spiders), mites can seriously damage a plant in just a few months. The dwarf Alberta spruce’s dense foliage makes an ideal habitat for mites (small spiders) which suck as sap from the leaves. Starting in the spring, one must periodically check for a mite infestation (especially in spring and fall) by holding a piece of white paper under a branch and shake the branch. If you have mites, then you will see very small spiders on the paper; you should then apply a miticide.
Zone: 2 to 6
Light: Full sun to part shade
Moisture: Average; somewhat drought tolerant
Soil: Adaptable to most soils
pH range: Acid
Dwarf Alberta spruce is useful in a dwarf conifer garden, as a foundation plant, used on either side of a landscape element (e.g., entryway, art work, sign) to frame that element, as a short hedge, in a container (at least for several years before it gets too big), or as an accent plant.
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October 31, 2018