Dwarf Plants That Don’t Stay Dwarf
July 26, 2013
By David MacManus
There are a many uses for low growing, compact shrubs that grow to a height of 3 feet or shorter, for our purposes, we will call them dwarf shrubs. Dwarf shrubs make an ideal addition to foundations, especially when there are low windows that they will be in front of. They are useful for placing in front of a low porch, in front of hedges, in front of taller plantings in a garden bed or behind even shorter groundcovers or bedding plants. They are ideal to plant along the edge of a patio to preserve the view, at a mailbox base, and to use as edging along walkways to help direct traffic. Unfortunately, such so called “dwarf” shrubs, often lose their utility over time when they grow higher than expected.
How high does any plant get? Spend some time reading various plant references or visiting various websites and you will frequently get different heights listed for the same plant. New gardeners may become quite confused. Visiting nurseries and reading plant labels or asking nurserymen does not always stop the dilemma. Much of the problem stems from the point of reference. Perhaps we should think in terms of how high plants grow over time. A shrub that is 3 feet high after 5 years of growth may be over 12 feet high after ten years if not kept in check. Another factor to consider is that a difference in plant growth rates can often be influenced by climatic differences. A plant that is very low growing in an arid or cool climate may be much larger with more moisture and warmer temperatures. Whenever you can get information on how plants have performed in our area over a period of many years you can be more certain as to what you can expect in your landscape. Good information is available through our county extension service and a number of electronic publications available from the University of Florida’s Electronic Data Information Source at http://edis.ifas.ufl.edu/.
Because many dwarf shrubs have the potential to eventually grow larger than desired, they may need replacing after a number of years. However, there are some methods you can use to help avoid this problem. Periodic pruning of many shrubs will help them stay compact for longer periods of time. Depending on the plant material this may mean they can remain in the same site for decades. A hard rejuvenation pruning is often effective on shrubs such as Hollies and Azaleas. However there are some shrubs such as junipers that will die back if you prune into wood without foliage. Sometimes the selection of a slower growing cultivar helps; for example ‘Schilling’s Dwarf’ Yaupon Holly is slower growing than ‘Nana’ Yaupon Holly and will remain in check for a longer period.
Some of the popular dwarf shrubs that are commonly used in our area include some varieties of loropetalum, azaleas, hollies, junipers, oleander, gardenia, crape myrtles, and bottlebrush. Monitor the size of the shrubs and prune as needed. Choose appropriate shrubs for the planting site considering their sunlight and moisture requirements. Be sure to take good care of your shrubs but avoid over fertilizing or giving excessive amounts of water. And be prepared to replace shrubs that may have served well in the landscape for years but have with time become overgrown.
David MacManus is the Assistant Director of Grounds & Landscape Operations at FSU and a member of the Leon County/UF IFAS Extension Urban Forestry/Horticulture Advisory Committee. For more information about gardening in our area, visit the UF/ IFAS Leon County Extension website at http://leon.ifas.ufl.edu. For gardening questions, email us at Ask-A-Mastergardener@leoncountyfl.gov