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.
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.
Start perennials at planting time and each spring thereafter with a complete, balanced fertilizer — one that provides equal percentages of the three primary plant nutrients: nitrogen, phosphorus and potassium.
Water and Feed Your Perennials
Young perennial plants may be hardy, but they still need plenty of water and nutrients to get established in the soil. You can easily water and feed at the same time with Miracle-Gro® Liquafeed®.
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.
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.
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.
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.
Applying fertilizer in the wrong season can cause increased tender new growth that can be damaged, especially if applied in cold weather in late fall or in winter. So it is best to stop fertilizing during dormant seasons. Additionally, in zones that can be in danger of a late freeze, it's best to wait until mid-spring.
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.
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.
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.
Fertilizing in the fall helps plants be hardier when the temperatures drop. We also recommend applying fertilizer in the late fall, toward the end of October or early November. This application will catalyze one last frenzy of root growth and really give your plants some staying power through the cold months.
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”.
For nearly all perennials, an early spring dose of fertilizer is key. This helps them develop strong roots and healthy foliage. The best time to apply this dose is just before or right as your perennials are emerging from the ground and starting to leaf out.
However, there are cultivated plants which are more susceptible to problems if the old foliage and dying stems are left to rot. Diseases can overwinter in dead foliage, as can slugs and other pests. Old stems can also get battered about by fall and winter winds, which will damage the plant's crown and roots.
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.
When To Stop Watering Plants in Fall. When the air and soil temperatures consistently fall below 40 F, it's time to stop watering. The ground can't absorb water once the top few inches freeze. Continue to water your plants up until this point so they're as well-hydrated as possible going into winter.
Morning watering is actually preferable to evening watering as the plant has time to dry before the sun goes down. At night, water tends to rest in the soil, around the roots, and on the foliage, which encourages rot, fungal growth, and insects.
The general rule is to apply twice per year — first in the early spring when new growth emerges and again in the fall before plants go dormant. While application requirements will vary, plan to apply around one pound of nitrogen or less per 1,000 square feet.
It does not need much fertilizer; however, if your soil is not in good shape or the plant is not thriving you may need to feed the plant. Rich soil and a lot of water is just as important for hosta health as is fertilizer. New hostas planted in the spring will need a good starter fertilizer to help establish the roots.