As a rule, perennials do not require a great deal of fertilizer. In fact, overfertilization of these plants can cause them to flop and become leggy while having a negative impact on bloom performance. As a leading provider of DIY gardening supplies in Bucks County and the surrounding areas, we’ve created this piece as a guide to perennials and fertilizer usage.
A Little Goes a Long Way
Perennials could benefit from one single application of fertilizer before the new spring growth starts to push its way up. We recommend no more than one pound of nitrogen per 1000sq.ft if there is no compost being used. This is the equivalent to a quarter of what you would apply to your lawn throughout a growing season.
Slow-Release vs. Balanced Fertilizers
Applying a slow-release fertilizer is the most sensible choice for meeting season-long requirements regarding plant nutrients. However, you can also use a balanced fertilizer like a 20-5-10. After testing your soil, if the results indicate that no phosphorus is required, you can use a product such as a 20-0-10.
Slow-release products are generally effective for 3-4 months, or 5-6 month windows of action. If you topdress or add supplemental feed at any time during the growing season, we recommend using a 3-4 month product on your perennials. If you are only going to fertilize once during a season, you should use the 5-6 month product for the best results.
The Sidedress Method
Another efficient way to fertilize perennials is known as “the sidedress method.” To do this, apply several tablespoons of fertilizer (following manufacturers guidelines) into the general root area of each plant.
It’s essential to ensure that no fertilizer granules cluster in the crown of the plants as this can cause burning. In the early springtime, cool soil conditions can affect the uptake of certain nutrients. This can make the foliage appear yellow or light green. This is a sign of nutrient deficiency, and should be spot-treated with liquid feed is it fails to diminish as the season progresses.