Determining why a plant is not flowering is a matter of knowing what the plant is, and observing what may be the problem. Some plants simply take time to mature and start producing flowers, sometimes years. Sometimes plants stop producing because of a lack of essential elements like water or sunshine, and there are other reasons as well. Let's examine some of these causes.
Biennial plants simply don't produce flowers until their second year. Some common flowering biennials are forget-me-nots, foxgloves and hollyhocks. Strawberries are also biennial, but will produce flowers (and fruit) if transplanted as mature plants. There are also everbearing selections of strawberries.
Many perennial plants, like irises, may not produce flowers their first year and some, like wisteria, may take up to 2-3 years or more. It is common for fruit trees to take a number of years to begin flowering and producing fruit. Peaches may take 2-4 years, apples and apricots 3-5 years and pears and plums 4-6 years. If your perennials stop producing flowers for no apparent reason, the cause may be an imbalance of nutrients, too much or too little water or you may be pruning off potential flower buds.
A lack of necessary nutrients can also cause a plant to be underdeveloped or to not produce flowers. Keep in mind that some plants like a “lean soil”, meaning a soil that is not rich with nutrients. A soil test should be able to determine if the nutrient balance of your soil might be the problem. When in doubt, contact a local gardening expert or university extension service.
Lack of sunlight can also cause some plants to fail to flower. For maximum production of flowers, plants like the annual geranium need a minimum of 4 to 6 hours of direct sunlight.
Pruning your plants at the wrong time of year can cause them not to flower. Some spring flowering plants, like lilacs and forsythia, set buds in the fall. If you prune these plants in the winter or early spring, you will lose the buds and have no flowers. Hydrangeas are another shrub that should be pruned according to when they flower. Some produce flowers on second year growth and others bloom on current season’s growth. If in doubt, prune shrubs as soon as they finish blooming.
A cold snap in early spring, following a period of mild weather, can kill off tender buds of plants including iris, rhododendron and hydrangeas. In mild climates, certain bulbs, like tulips, won’t thrive and bloom because they don’t get the necessary winter chilling they require.
Jordan Laio is a Hometalk - http://www.hometalk.com - writer. Read more articles like this one - http://www.networx.com/article/why-wont-my-flowers-bloom - or get help with your home projects on Hometalk.com.