What is a "dwarf conifer"?

The designation "dwarf" conifer means that it is a cultivar (cultivated variety) that is slower growing and will have a smaller mature size  than the naturally occurring species.  For example, if the species can attain 60 feet mature size in its natural range, a cultivar that matures at 50 feet is still considered a dwarf form!  The American Conifer Society has designated 4 distinct categories of dwarf conifers based on mature size and growth rate.  A more appropriate term for the homeowner might be "garden conifer".

Keep in mind, the following factors will affect differences in annual growth rate, as is true with any plant.

• Regional variations
• Climate
• Precipitation and atmospheric moisture
• Soil fertility, pH, composition, etc.
• Stress
• Your own yard's microclimates

What makes a conifer dwarf?

• Seed provides genetic variation and mutations.  Mutations of the species (wild type) parent plant are identified, selected, and propagated.

• Witch's Brooms

• Variations in top growth (scion) due to which rootstock it is grafted on

Clonal (vegetative propagation) – most mutations and brooms are grafted onto rootstock to produce a cultivar.  Many genera do not propagate easily from cuttings.  Exceptions are yew, arborvitae, and some falsecypress. 

Find more information on the American Conifer Society website.

American Conifer Society Designations

Large

• Growth rate greater than 12” per year

• Approximate size at 10 years greater than 15’

      Example: Pinus strobus (Eastern white pine) species and ‘Fastigiata’

Intermediate

• Growth rate from 6” to 12” per year

• Approximate size at 10 years 6’ to 15’

      Example: Pinus sylvestris (Scots pine) species and ‘Globosa Viridis’

Dwarf

• Growth rate 1” to 6” per year

• Approximate size at 10 years 1’ to 6’

      Example: Pinus mugo (mugo pine) species and ‘Slowmound’

Miniature

• Growth rate less than 1” per year

• Approximate size at 10 years less than 1’

      Example: Picea pungens f. glauca (blue Colorado spruce) species and ‘Tiny Tim’

Large dwarf conifers are more appropriate for larger sites and may not be as useful for the homeowner with a smaller lot.  Intermediate and dwarf categories work well for the average to small yard.  Miniatures need space around them and don't compete with other landscape plants.  They are more desired for rock gardens, containers, garden railways, and small water features.