All woody plants have a regular sequence of bloom. Whether they are growing in Florida, California, Massachusetts, or Illinois, this sequence is always the same and can be depended upon from year to year.
The redbud always blooms with the flowering dogwood, and the pink shell azalea always blooms with the lilacs, regardless of where they may be growing.
The actual data upon which a plant blooms does vary. It varies from one year to the next because of an “early” or “late” spring.
It varies with the situation; plants in a Florida garden would be expected to bloom nearly three months earlier than the same plants growing in Maine.
Factors Affecting The Blooming Date
The blooming date also varies with exposure and altitude. A plant growing high on a mountainside would bloom later than a similar plant growing at the mountain’s base in a protected sunny spot.
Mountain laurel, Kalmia latifolia, blooms at different times in different areas of the country, as listed below.
The mock oranges, the tulip tree, and many of the rose species always bloom with it.
- Mid-April …….Augusta, Ga.
- Late April…….Glen St. Mary, Fla.
- Mid-May…….Shenandoah Valley, Va.
- Late May…….St. Louis, Mo.
- Early June…….New York, N. Y.
- Mid-June…….Chicago. Ill.
- Late June…….Seattle, Wash.
Annual Record of Bloom Date
The practical-minded gardener might find it interesting to keep an annual record of the date a certain tree or shrub in his own garden first comes into bloom each year.
This proves to be a good example of the “earliness” or “lateness” of the spring. We have done this with many plants in the Arnold Arboretum.
For example, here is our record of just one tree: the golden willow tree (Salix alba vitellina ). Its young foliage swells and quickly opens in the early spring, sometimes almost overnight. These are the dates on which this tree has first appeared green for the past ten years:
- 1940…….May 1
- 1941…….April 15
- 1942…….April 6
- 1943…….April 28
- 1944…….May 1
- 1945…….March 27
- 1946…….March 27
- 1947…….April 14
- 1948…….April 5
- 1949…….April 4
- 1950…….April 28
List of Commonly Available Plants
The list of commonly available plants is grown together in the Arnold Arboretum in Boston, Mass., under similar soil and climate conditions. The sequence in which they bloom has been carefully observed for many years.
This list can be applied to any area in the United States. If local blooming dates of a few key shrubs are noted and the differences checked in the list on the next page, then all the dates in the list can be correspondingly shifted, and the list is thus adapted to local climatic conditions.
44659 by Donald Wyman