1. Juvenility/Age - Plants have to reach a certain stage in their development before they are able to have flowers and set seed. Before this happens, the plant is said to have juvenile tissue. Once it starts to flower, it has transformed into mature tissue.
   
   This is not always a straight forward process. Some trees may take 15 or 20 years to become mature while others such as oaks and beech have both juvenile and mature branches on very old trees.
    

2. Inadequate Light Level - All plants have a certain level of light that is needed to trigger flower production. This level will vary between full sun and shade type plants but they all have their requirement. If it is not met for a particular plant in a particular site, it will not flower.
    

3. Inadequate Chilling - Ever wonder why you don't see apple trees in Southern Florida? One big reason is that the flower buds of apple trees need to be exposed to cold temperatures for a certain number of weeks or they will not bloom.
    

4. Winter Kill - Many of the shrubs and trees that bloom in early spring to early summer develop their flower buds the previous autumn. Flower buds are the most tender tissue on the plant. So, if the winter temperatures drop unusually low, especially with strong winds, the buds may be killed.
    

5. Buds Are Removed - Again, some plants put on their flower buds in the fall. So, pruning them in the fall or winter simply removes flower buds. These types of spring flowering plants should be pruned after they get done flowering.
    

6. Transplant Shock - Some plants just take a season or two after being transplanted to begin to flower. Iris are noted for not always flowering the first year after being divided and moved.
    

7. Nitrogen - Over applications of nitrogen fertilizers may lead to an excessive growth of foliage at the expense of flowers.
    

8. Pest Problems - Japanese beetles, thrips, botrytis blight and others may damage the buds and cause them to abort.
    

9. Drought - Flowers are a fleshy, lush type of plant tissue. Severe drought can dry out the buds or the flowers on plants. Keep flowering plants watered properly.
    

10. Wrong Plant, Wrong Place - Plants that are not properly adapted to your climate zone may have problems flowering (or surviving).

• Animal Damage
• Bark Damage
• Black Needled Conifers
• Broken Limbs
• Cankers
• Crotch Angles
• Dieback
• Distorted Leaves
• Fall Needle Drop
• Failure to Flower

• Frost Cracks
• Galls
• Honeydew
• Leaf Spots
• Lightning Strike
• Limb Drop
• Mechanical Damage
• Mushrooms
• Nutrient Deficiency
• Sap Oozing
  

• Scorch
• Shelf Fungi
• Skeletonized Leaves
• Sunscold
• Transplant Shock
• Trees Falling Over
• Wilt
• Witche's Brooms
• Yellow Leaves

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.