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What to Do When Your Flowering Shrubs Are ‘Flowerless’

I was talking to some of my family the other day and they mentioned how they used to have flowers on some of their shrubs but now they have not seen one in over a year.  I thought appropriate to touch on one of the greatest and most common frustrations in gardening; when plants, including our annuals, perennials and shrubs do not bloom. Common questions we get around here at the office are, “Where are my flowers?” or “Why didn’t my plant or shrub bloom this year; it was loaded with flowers last summer?”  There are several reasons that flowering may turn out to be a bit disappointing. 

It usually takes some detective work to get to the bottom of the problem, but the answer can usually be found if enough questions are asked. There are so many factors to consider, where do we even begin to think of questions?? Well start to ask yourself things like:  Is there enough light? What has the weather been like? Have you had any freezes? Was there a drought last year? Was there too much water, or too little water? Has anyone gotten some new pruning shears and tested them out on your azaleas or other plants? 

Some plants, such as a Ginko or magnolia tree, may take 20 years to bloom. Many of our dogwoods grown from seed may take five to seven years to bloom, and then they bloom lightly. Many plants go through an aging process and must mature into their sexual stage of development. One reason clones or cultivars of plants are selected, such as Cherokee Princess or Barton’s White dogwood, is that they bloomed at a very early age. So, if your plant is not blooming yet, it may just still be too young. Too much shade is also a common problem for poor blooming. Fast-growing trees may have taken the spotlight off your prized plant resulting in fewer blooms each year. Many flowering plants need a sunny exposure to grow properly and produce flower buds and if these sun-loving plants are in too much shade then flower bud production will be greatly reduced. For instance, a rose, needs at least six hours of direct sun each day to offer its best flowering. The weather can cause many problems. It can be too cold or not cold enough. It can be too wet or too dry. Both extremes can cause flowers not to form or to abort after they do form.

Late pruning can also remove flower buds. Azaleas and most other early spring flowering plants form their buds after they bloom the previous summer. If you prune these plants, be sure to do it after they bloom. Do not wait until winter. Hard rejuvenation pruning, where you cut a plant back to the ground, can also reduce or eliminate flowering. The plant becomes so vigorous that it produces excessive vegetative growth and does not slow down to set the flower buds. If you fertilize a very healthy plant four times a year and it still does not bloom, examine the type and quantity of fertilizer you are using. If the fertilizer is not the problem, check to see if the plant may have a long juvenile stage. Sometimes overfertilizing causes too much vegetative growth to occur and little or no reproductive or flower growth to occur. Gardeners sometimes try to fertilize their plants into flowering with excessive amounts of nitrogen. As with hard pruning, the extra nitrogen forces too much lush, vigorous growth and flowers do not develop. It may take a few years for the plant to get back to normal. Try to soil test every few years and follow the recommendations on the report.

At the other extreme, there are some plants that may face reduced or loss of blooms as they mature. They may get cluttered with large old canes like nandina. If you remove one-third of the old canes each year, as well as dead, dying and diseased branches, you will stimulate new growth with more flower buds. At the end of the day, if there is an issue with flowering, odds are one of the factors above can be part of the why. If you have any problem like this and want to talk about potential causes, please feel free to reach out! 

Joke of the Day: What did the supportive shrub say to the other? I am ROOTing for you!