Sequence of Bloom and Successional Interest Explained for Newbies

And How They Affect Landscaping Plant Choices

Snowdrops in bloom.
Snowdrops are early bloomers. David Beaulieu

When gardeners and landscape designers speak of "sequence of bloom," they are referring to the different time periods in which various landscaping plants bloom during the course of a growing season. Once schooled in this knowledge, you can plan your landscape accordingly, so as to have something in flower at all times during the months conducive to flower gardening in your region. Guided by such information, plant selection at the nursery becomes more purposeful, rather than being based on whim ("Oh, that looks pretty, let's buy it").

Chart Your Own Course

The best way to study sequence of bloom is to draw charts to record the times when the plants that you are interested in growing are in flower. Such a chart should have the names of plants running down the left-hand side of the page (alphabetically), with month names running across the page at the top. Horizontal and vertical lines are then drawn accordingly to divvy the page up into cells. The cells can then further be broken down to indicate weeks. If the plant in question blooms for two weeks in May, let's say, check marks are placed in the corresponding cells.

The nice thing about these sequence of bloom charts is that the order will always be the same, regardless of region or freaky weather. This means gardeners across various regions can profit from sharing knowledge on the subject even though their climates are different.

For example, if someone in Maryland (U.S.) draws one such chart, and if a Massachusetts gardener draws another, the pattern will be the same, despite their living in different USDA planting zones. The snowdrops (Galanthus nivalis), say, will bloom later for the Massachusetts gardener (being further north), but they'll still come into flower at about the same number of weeks before avens (Geum) as they do for the Maryland gardener.

If a sequence of bloom chart sounds too complicated, begin with a simple garden journal. When the first spring flowers come into bloom, note this fact in your journal (their names and when they bloomed). Thereafter, as the growing season progresses, continue to jot down such information. In addition, indicate when each plant stops blooming.

As a newbie, the record in your journal's first year may well be pretty sparse, with numerous gaps. But that is all part of the process. The idea going forward will be not only to acquire more plants but specifically to acquire specimens whose blooming period will allow you to plug those gaps. You can now easily understand how important sequence of bloom is in designing a colorful landscape.

Mix and Match From Different Plant Categories

Shrewd gardeners typically mix and match in pursuit of continuous sequence of bloom from among various groups of flowering plants:

For the most part, gardening enthusiasts on average-sized properties focus on perennials and shrubs. The latter form the "bones" of the landscape, while perennials, being smaller and less expensive, lend themselves more to mass plantings and to transplanting. Ease of transplanting is an important consideration for a gardener interested in sequence of bloom because, as the years go by and you accumulate more and more plants, you'll probably find yourself rearranging your flower beds to make room for new arrivals.

There are numerous choices for perennials that flower in spring and summer (fewer for fall, and they must be pinched during summer to delay their flowering), but here are some selections to get you going (seasonal references in this example are for zone 5):

You will find that growing long-blooming perennials makes your sequence-of-bloom goal easier to attain because the longer your selections stay in bloom, the less you have to worry about plugging gaps. For the same reason, annuals come in particularly handy since they will generally bloom for months on end if you deadhead them. Annuals will still be supplying floral color at the tail end of summer and right into fall (until the first frost), weeks or even months after many plants have long since packed it in for another year.

To help you with selecting shrubs in the pursuit of sequence of bloom, use the following lists:

The Meaning of "Successional Interest"

Some garden writers use "sequence of bloom" and "successional interest" as if they were synonymous. But "sequence of bloom," in the narrow (literal) sense, pertains only to specimens with blossoms. Reserve the terminology "successional interest" to refer to a broader range of plant characteristics than just blossoms that you can use to keep your landscaping colorful as consistently as possible. Sequence of bloom is a subset of successional interest.

Here's an example where we should speak of "successional interest" rather than "sequence of bloom." Even after the frosts of early fall have killed flowers in the North, you can enjoy the color offered by fall foliage trees and shrubs with good fall color (assuming you've had the foresight to install such plants).

Nor must give up the pursuit of successional interest after the autumn leaves drop to the ground as long as you've planted evergreens and other plants with winter interest. Even during seasons when there are flowers to enjoy, you can supplement the visual interest they furnish through the use of foliage plants. More generally speaking, you should always consider the forms and textures of plants when planning your landscape design if your goals are a maximum of diversity and year-round interest in the yard.