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Spring Perennial Garden Fertilization

. . . fertilizing established perennial gardens

Preparing the garden for spring Perennials are in for the long haul. Plant them once, and they come back every year, so you don't have to plant again. With proper care and conditions, perennials return, often increasing in size, each year, unlike annuals, which live a single season, give their all and die. Perennials naturally take at least three years to complete their life cycle. They generally flower for shorter periods of time, each type with its own timing, but their variety in bloom times, and their textures, colors and forms keep landscapes looking fresh and vibrant. Proper fertilizers help perennials keep their beauty and vigor, and prepare for coming years.

Compared to natural settings, perennial beds are crowded and competitive. All those lovely flowers contend for the same nutrients. Even plants that naturally thrive in poor soil benefit from fertilizers in garden settings. Feed them properly, and forget about weak, lanky plants or few blooms. High-nitrogen fertilizers, including common houseplant foods, can stimulate leafy, green, grassy growth. But flowering perennials need fertilizers that support prolific blooms.

Smart gardeners know that heavy fertilization of perennial garden plants leads to flopping over half-way through the season.

Perennial flowers, ground covers and grasses generally don’t need a lot of fertilizer and, in fact, some will react negatively if too much is applied. An over-fertilized perennial will reward gardeners with excess growth that flops over and becomes leggy half-way through the season. Over-fertilization can also affect bloom performance, producing ample foliage at the expense of blooms. Many perennial experts recommend no fertilization when plants are in a healthy garden soil.

However, if your soil is composed primarily of sand with little organic component, your plants will most likely benefit from routine, light fertilization.

Understanding the types of plants and their natural growing range will enable you to create a growing environment similar to the plant’s native habitat. It is helpful to keep a watchful eye and journal of plant “behavior” in hopes to correct situations later such as leggy growth and poor performance.

Slow-Release Fertilizer

Apply slow-release fertilizer Broadcasting a slow release fertilizer is the best choice to meet season-long plant nutrient requirements, but you can also use a balanced fertilizer such as 20-5-10. If your soil test indicates that you do not need phosphorous, choose a product such as 20-0-10.

Slow release products are formulated to be effective for either a “three-to-four” month window or a “five-to-six month” window. If you top-dress and plan on using supplemental feed at any time during the season, the three-to-four month product should work well. If you only intend on fertilizing only once during the season, then the five-to-six month product should be used.

Side Dress Fertilizer

You can also use the “sidedress” method, applying several tablespoons of fertilizer (according to the manufacturer’s guidelines) in the general root zone of each plant. Make sure not to allow fertilizer granules to cluster in the crown of the plants as it may cause burning. In the early spring, cool soils can have an effect on uptake of certain nutrients, at times making the foliage appear light green or yellow (nutrient deficient). If this appearance does not diminish as the season progresses, spot treat with liquid feed to bring about a quick green up.

Compost insurance

Compost pile By applying 1 inch of compost or leaf mold to your garden every year, additional fertilizing can often be eliminated altogether. This is where having a good understanding of each plant’s needs while observing leaf color and growth habit will help you avoid excess fertility.

Top-dressing a perennial bed with 1 to 2 inches of compost will provide season-long fertility for most perennials.

Further Information:

 How To Use Rooting Hormones
 The Life Cycle of Plants: Fertilization
 The Spruce: How to Make Your Own Fertilizer
 Pollination and Fertilization