Nothing is quite as disappointing as flowers that fail to bloom. I know. I’ve been there. Last year I decided to plant my dahlias in a new location. What I didn’t realize at the time was that even though the entire garden wall and the area in front of it received full sun, the two-foot zone where I planted them didn’t. This resulted in very few blooms. But, that’s not the only reason flowers fail to bloom.
Lighting
Each flower prefers a particular amount of light. Making the mistake of planting flowers in an area that receives too little light often results in a lack of blooming. According to Purdue University moving the plants to more light often promotes blooming – that is, if you haven’t planted them in the soil where they cannot be moved. Take my advice. Always double-check the lighting in your flowerbed before deciding which flowers to plant.
High Nitrogen
Applying too much fertilizer, especially one high in nitrogen, produces lush green foliage with few blooms. Applying fertilizer to your flowers is one of those times when “more is not better.” Use caution with fertilizer to avoid vigorous growth with few or no blooms. Generally, for flowers grown in the soil, fertilizing at planting and once or twice throughout the summer is adequate. Those in containers benefit from water-soluble fertilizer mixed to half or one-fourth strength applied on a 10 to 14-day cycle.
Weather
Both high and low temperatures affect the ability of your plants to bloom. While cold temperatures may kill the buds before they have the opportunity to open, high temperatures may inhibit blooming too. Growing flowers that thrive in temperatures typical to your area is the easiest way to control the lack of blooming caused by high or low temperatures.
Water
All plants need water to thrive, but not all plants need the same amount of water. Both too little and too much water can cause buds to drop and lack of blooms. Typically, flowering plants prefer an inch or two of rain a week, but there are exceptions. Always follow the recommendations for your specific plants.
Insects
Sometimes an insect infestation may be the cause of lack of blooming. Earwigs, aphids and slugs are common culprits, but this varies according to the type of plants and your location. Never underestimate what insects may attack your plants. Last year, miniature wooly bear caterpillars nearly devoured several houseplants I had summered outdoors. Although it is not typical of wooly bears, they were more than happy to feast on my plants.