How To Fertilize Perennial Plants
Perennials plants are those that come back year after year in the landscape or garden, bringing joy to all who plant and watch them grow. Perennials are most often planted outdoors in prepared beds or in containers (container gardens).

Investing in perennials is an investment in tomorrow. When planted in the right environment, and with proper care and fertilization, perennials will spread as they grow from year to year. They will increase in size and in the number of blooms produced each season. 

Why fertilize perennial plants?
The two primary reasons for fertilizing perennials are to encourage growth and to create a healthy, vigorous, attractive plant that will produce an abundance of flowers. But be careful...there is often a temptation to over-fertilize in the hopes of producing more blooms, faster. If you force a perennial plant beyond its natural growth rate by over-fertilizing, you might end up with mostly foliage and no blooms. Too, over-fertilization can predispose the plant to insect or disease infestation, and reduce tolerance to drought or temperature extremes.

Evaluate soil conditions first
There's usually not a need to perform a soil test before planting or fertilizing perennials; however, it may be a good idea to research the various types of perennial plants you have growing in your garden to see if there are any specific nutritional needs. Some perennials like an acid soil, some like an alkaline soil, while others grow in a wide range of pH. Your local Extension Service can help you with soil testing, or you can do it yourself with a soil test kit or soil pH testing probe. 

What fertilizer is best for perennials?
Most perennials would be happy with a good, all-purpose flower food or organic fertilizer; however, others may have specific preferences or needs. In general, using a natural, organic fertilizer is the preferred method because there is very little chance for burning your perennial plants. Flower foods such as "Bloom Boosters" can be useful for development of stronger root systems and promoting more and larger flowers. Slow- or timed-release, capsule-type fertilizers can be applied once a year for season-long feeding. These work especially well in container gardens, where the capsules won't wash away. 

How often should perennial plants be fertilized?
As a general rule of thumb, you will usually fertilize perennial plants at least twice a year: in the early spring when new growth begins to emerge, and again in early fall. Too, any time you cut a perennial back during the active growing season, a feeding is usually beneficial. This feeding will provide the plant with an extra boost to produce new foliage and possibly another flush of blooms.

More Helpful Tips

  • Be careful not to apply fertilizer too heavily. Doing so may cause the plant tissue to burn, or even result in plant death. Read product labels carefully and follow directions to avoid toxicity problems.

  • If over-fertlilization of your plants is too much a worry for you, consider easing your mind by using a mild, natural or organic fertilizer. Organic fertilizers are made with natural ingredients such as composted manures or other organic matter, which are much less-likely to burn your plants.
  • Perennial plants may grow quicker with excessive nitrogen (the first number on a package of fertilizer), however this might increase foliage growth and decrease bloom production, or lead to the onset of damaging or deadly diseases. So it's best to use fast-acting fertilizers with a high-nitrogen content.

  • As a general rule, the slower the plants habit of growth, the less fertilizer it needs. Some plants, such as sedum and other succulents, require little if any fertilization.

  • Plants that are producing an abundance of blooms or fruit generally need more fertilizer.