There are several reasons why plants fail to bloom and/or bear fruit in the home landscape. Here are a few of them.
  1. Plant Age - Starting from seed, certain plants have to reach a minimum age before they start to produce flowers and seeds. Plants go through a juvenile phase in which they cannot form seed and, in some cases, bloom. Some trees may take up to 15 or 20 years to reach maturity.

  2. Male or Female - There is a category of plants that are called dioecious. These species have separate male and a female plants. Common examples in the landscape are hollies (Ilex), bittersweet vines (Celastrus) and Ginkgo trees. In order to form fruit on these plants, you must have both a male and a female plant in close proximity. Of course, the fruit will only appear on the female plant so the mixture is usually one male plant for three or four females.

  3. Cold Weather - Most shrubs and trees that bloom in the early spring set their flower buds in the fall. These must survive the winter cold in order to bloom. Even though a plant is rated as hardy for your climate zone, the flower buds are generally the least hardy part of the plant. They may sometimes be killed because of extreme, unusually low temperatures or by the combination of temperatures and winter winds.

  4. Pruning - For early flowering plants that set their buds in the fall, a major problem can be pruning during the winter. This essentially cuts off the flower buds for the following season. It does not hurt the plant but decreases the bloom display.

  5. Fertilizer - Over applications of nitrogen may lead to poor bloom. Nitrogen encourages development of foliage and this may be at the expense of flower buds. Although rare, a deficiency in phosphorus may lead to poor bloom.

  6. Light Conditions - Each species of plants needs a specific minimum amount of sunlight in order to set flower buds. Obviously this varies considerably from plant to plant but each on has its own requirement.

  7. Insects - Certain insect pests such as thrips and Japanese beetles feed on flower buds and may cause reduction or elimination of blooms.

  8. Disease - A number of fungal diseases such as Botrytis blight will cause abortion of flower buds. The bacterial disease, fireblight, may also cause loss of bloom in members of the Rosaceae Family such as crabapple, hawthorn, mountain ash, firethorn and cotoneaster.

Sometimes too much fruit production is a problem and fruit prevention is the goal.

Note: We have provided some general information and observations on this topic aimed at the home gardener. Before you take any serious action in your landscape, check with your state's land grant university's Cooperative Extension Service for the most current, appropriate, localized recommendations.

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