Perennials that require no fertilizer: Included are ornamental grasses, false indigo, ground covers, butterfly weed, bee balm, coneflowers, black-eyed Susans, sea holly, dianthus, asters and veronica. summer: Use a quick release food in summer, instead of a slow release food.
Perennial flowers are a bit different than annuals. They generally require less fertilization and since they often slow down growth in autumn to prepare for dormancy, fertilization should be avoided after late summer.
Perennials that do best with no supplement fertilizer include butterfly weed (Asclepias tuberosa), false indigo (Baptisia australis), asters, pinks (Dianthus spp.), rock roses (Helianthemum spp.), sea holly (Eryngium spp.), bee balm (Monarda didyma), speedwell (Veronica spp.), coneflowers (Echinacea spp.
Water and Feed Your Perennials
You can easily water and feed at the same time with Miracle-Gro® Liquafeed®. When watering, avoid perennials' leaves to prevent disease, and aim for a soil consistency that is neither too wet nor too dry.
Some perennials, like hostas, peonies and daylilies, need to be pruned in fall to avoid winter damage. Plants like these should be pruned after the first few frosts in late fall or early winter. Other perennials like mums and coneflowers are better off being pruned in spring just before new growth comes in.
No matter which fall gardening project you choose, be sure to make plant roots super-happy by using Miracle-Gro® Potting Mix (for containers) or Miracle-Gro® Garden Soil for Vegetables & Herbs (for in-ground).
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.
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.
It is important to water plants thoroughly with plain water before applying the liquid fertilizer to avoid burning the roots if the soil is dry. Also, take care that the fertilizer is indeed diluted based on instructions, or you could burn the leaves.
To ensure vibrant green leaves, feed your hosta in the spring when the leaves begin to pop out of the ground. For best growth, fertilize it every 4 weeks. Do not feed the hostas mid to late summer. This can cause new growth to start which could be easily damaged by oncoming frost.
Perennials that require minimal fertilizer include ornamental grasses, false indigo, asters, sea holly, bee balm, and butterfly weed. On the flip side, some do better with extra nutrients. Heavy feeders include mums, lilies, lupines, tall phlox, peonies, delphiniums, and astilbes.
Spring Perennial Plantings:
Week 1: Every day to every other day. Weeks 2-3: Water 2-3 times per week, depending on environmental conditions. Weeks 4+: Water 2-3 times per week, more in hot/dry conditions. When cooler, water less.
Perennials: Rake away mulch in spring and apply 1-inch of compost around plants. Lightly fertilize plants if needed with a complete granular fertilizer. This can be repeated mid-summer if growth is weak or foliage is light green in color. In late summer, fertilize plants that will bloom late summer through early fall.
Most perennials grow best in soil that is well drained with good fertility and a pH of 6.0 to 7.0. Adding organic matter to soil improves the fertility, texture, and water-holding capacity. Apply a two to three inch layer of mulch to conserve water, reduce the need to weed, and keep soil temperature cool.
However, complete fertilizers sold for flowering plants (including roses and bulbs) such as 15-30-50 or 10-30-20 contain higher amounts of phosphorus (the second number) than nitrogen or potassium and are often labeled as “blossom or bloom booster”.
Perennials may benefit from a single fertilizer application just before or at the time that new spring growth is pushing up. The most common recommendation is to apply no more than 1 pound of nitrogen per 1,000 square feet if no compost is used.
Balanced granular fertilizers such as Espoma Rose Tone and Holly Tone are good choices. Jobes Fertilizer Spikes are another good option. Avoid using fast-release fertilizers in liquid form on hydrangeas. These products can stimulate growth in the short term but may not sustain the plant for the long haul.
MG is so strong that if used incorrectly, the fertilizer will actually burn the leaves and roots of your plants (you may have already experienced this). Imagine what it's doing to the healthy bacteria, fungi and other soil microbes that are working so hard to provide the nutrients your plants need.
The main issue with this fertilizer is that it contains a lot of nitrogen. This component comes from synthetic materials, which produce chemicals potentially harmful to the soil and the plants that aren't listed as active ingredients.
The excess use of ammonium based fertilizers can cause damage to the micro-organisms in soil and water. In addition to that, constant overdosing may lead to negative results as plant damage or deterioration.