Key Points
Experts agree that fall is generally the best time to plant perennials.Growing zone and the type of perennial can influence whether spring or fall is best.However, not all perennials benefit from fall planting.
Spring might seem like the obvious time to plant perennials—after all, it’s when we sow most annuals, from flowers to vegetables. Temperatures are warming, rain is plentiful, and the energy and motivation to garden are also at an all-time high. But is spring truly the best time to get these hardy plants in the ground—or should you wait until fall, just before the first frost? To find out, we spoke to three gardening experts—and they all said the same thing.
Meet the Expert
Kelly Funk is the president and CEO of Jackson & Perkins, a full-service nursery brand known for expertise in rose cultivation and other perennials.
Shelly Deaton is a gardening expert and co-owner at EarthSpoke Farms, a multigenerational family flower farm located in Mendocino, California.
Anna Ohler is the owner of Bright Lane Gardens, a boutique plant nursery located in Lake Ann, Michigan.
When Should You Plant Perennials?
Generally speaking, the experts agreed that fall is the best time to plant perennials. Specifically, perennials should be in the ground about four to six weeks before your area’s expected first frost date.
That said, not all perennials benefit from fall planting. For example, herbaceous perennials (i.e., those whose foliage dies back in the winter) are usually best planted in the fall, while evergreen or semi-evergreen perennials (i.e., those that keep their foliage in the winter) are often best planted in the spring so they have a full growing season to establish before facing cold stress, says Kelly Funk, president and CEO of Jackson & Perkins, a full-service nursery brand known for its expertise in rose cultivation and other perennials.
Spring-blooming perennials like bearded irises and peonies should always be planted in the fall, while fall-blooming perennials like chrysanthemums or Japanese anemones should be planted in the spring, says Shelly Deaton, gardening expert and co-owner at EarthSpoke Farms. Any perennials that are marginally hardy for your zone (think: frost-sensitive dahlias) should always be planted in the spring once the danger of frost has passed.
Your growing region can also influence whether fall or spring is best for planting perennials, Funk says. In climates with mild winters (zone 7 and above), perennials can almost always be planted in the fall since they won’t experience drastic cold stress over the winter. However, gardeners in colder climates (zones 3 to 5) may need to push some of their planting into spring to prevent tender roots from dying over winter.
Ultimately, t’s always best to research the recommendations for your USDA growing zone as well as the perennial you are looking to plant.
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Why Fall is the Best Time to Plant Perennials
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Photos by R A Kearton / Getty Images
According to gardening experts, here are a few reasons that planting perennials in the fall is best.
Mild temperatures reduce stress.
Spring and fall are the best times to get new plants in the ground because temperatures are neither too hot nor too cold. Compared to the heat of summer months, the cooler fall weather causes less stress on plants during transplanting, says Deaton.
Fall rainfall keeps plants watered.
We all know that April showers bring May flowers, but autumn rains are just as bountiful. Those gloomy fall rainstorms are actually helping your garden prepare for a long winter’s rest, and they help freshly transplanted perennials acclimate after planting.
Warm soil encourages root growth.
Temperatures may be cooler, but the soil is still warm enough to encourage plenty of root growth before the frost hits. Thanks to cooler air temperatures, reduced heat stress, and plentiful fall rains, perennials are well set to establish healthy roots when planted in the fall.
Fewer pests, weeds, and diseases.
Cool fall temperatures help reduce pest and disease pressure in the garden. By the time you’re ready to plant your fall perennials, many summer insects have died off for the winter, with their eggs and pupae lying dormant until the spring. The reduced humidity also helps slow the spread of fungal and bacterial diseases in the garden.
Plants get a head start.
It all comes down to this: for the right perennials, fall planting will give them a head start so they can grow bigger and better in the spring.
“The shorter days and sunlight will allow your plants to establish their roots over winter slowly, and they will have developed a strong root system by spring or summer when temperatures warm up and your perennials are ready to bloom,” says Deaton.
This means you can expect more prolific blooms from perennials planted in the fall than from the same ones planted in the spring.
Tips for Fall Planting
Planting perennials in the fall comes with a few key rules and guidelines to keep in mind.
Time it right.
The first and most crucial step to planting fall perennials is to ensure you do it at the right time.
“There is such a thing as planting too late!,” says Anna Ohler, owner of Bright Lane Gardens. “Aim for planting perennials four-to-six weeks before the first average frost date for your region. Do not plant any later than four weeks before that date or the roots may not have enough time to grab on.”
Water well after planting.
Fall rains can help keep your perennials hydrated, but it’s still important to water them thoroughly immediately after planting. This helps minimize transplant shock, prevents wilting, and encourages deep root development.
Skip heavy fertilizer.
Fertilizer gives your plants the nutrients they need to thrive, but when it comes to fall planting, less is more. That’s because you want your freshly transplanted perennials to focus their energy on root development rather than pushing out tender new foliage ahead of your area’s first frost, says Funk. Just think of it as one less step on your fall gardening to-do list.
Add mulch.
The experts agree that mulching your newly transplanted perennials in the fall is a good idea. A light layer of mulch can help insulate and protect the plant’s roots as temperatures begin to cool.
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