If you want perennial plants to settle in as quickly and easily as possible, it pays to get them in the soil at the right time. Perennials planted in summer are more at risk of transplant shock, while perennials planted in winter can succumb to cold damage.
Whether you’re growing plants from seed or transplants, here’s exactly when to plant perennials so they thrive, plus a list of eye-catching flowers you might want to add to your garden this growing season.
As an avid gardener, I’m always looking for ways to extend the growing season and plant as late into fall as possible. Perennials are a great option for fall planting, as many varieties do well when put in the ground in autumn In this article, we’ll explore how late you can plant perennials based on your hardiness zone, the best perennials for late season planting, and tips for success.
When is the Last Chance to Plant Perennials?
The timeframe for planting perennials in fall depends on your USDA plant hardiness zone. Here are some general guidelines
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Zones 3-4: Finish planting marginal perennials by early October. Plant cold-hardy natives until late October. End all planting by early November before ground freezes.
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Zones 5-6: Stop planting tender perennials by late October. Plant hardy varieties until mid November. Halt all planting by late November to avoid frost damage.
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Zones 7-8: Plant tender perennials by late November. Hardy perennials can go in the ground through December. End plantings by mid December before chill sets in.
These are just general rules of thumb – also consider your specific climate and weather patterns. Track soil temperatures in your garden to see when the ground starts cooling off. Water new plantings diligently until the ground freezes. And prevent frost heaving in winter with mulch.
The Best Perennials for Late Season Planting
While most perennials can be planted in autumn, some are better choices for fall than others Focus on these top types
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Cool season bloomers – Crocus, hellebores, iris, forget-me-nots, and pansies thrive when planted in fall. Winter chill actually initiates their flower development.
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Native wildflowers – Black eyed Susans, coneflowers, asters, and goldenrod establish quickly when planted in fall since they are adapted to Midwest winters.
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Ornamental grasses – Switch grass, maiden grass and fountain grass spread vigorously when planted in autumn and stand up well to winter snow.
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Sedums – Meaty sedum varieties like Autumn Joy and Matrona store water in their leaves and can be planted up until early winter.
Stick with hardy varieties suitable for your zone, and you can plant perennials into late fall with good success.
How to Plant Perennials in Autumn
Follow these tips when planting perennials in the fall season:
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Water thoroughly at planting time and continue watering until ground freezes.
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Prepare soil well with compost to encourage root establishment.
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Plant at proper depth, being careful not to bury crowns too deep.
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Apply 2-3 inches of mulch like wood chips or straw to prevent frost heaving.
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Stake tall perennials that could flop over from heavy snow.
Follow these basic steps when putting perennials into the ground in fall:
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Choose a spot with decent drainage and ample sunlight. Amend soil if needed.
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Dig a hole twice as wide as the root ball but no deeper than its nursery pot depth.
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Place the plant in the hole with its root ball level with the ground.
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Backfill with native soil, tamping lightly to remove air pockets.
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Water thoroughly until the soil is saturated.
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Mulch 2-3 inches around the plant, leaving the crown clear.
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Keep watering 1-2 times per week until the ground freezes solid.
Properly preparing the planting area, caring for perennials at planting time, and providing attentive aftercare will set them up for success.
Dividing & Transplanting Perennials in Fall
In addition to putting new perennials in the ground, fall is also an ideal time for dividing and transplanting ones you already have:
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Divide spring & summer bloomers in early fall to allow plants like hostas, astilbe and bee balm time to reestablish roots before winter dormancy.
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Divide fall bloomers in spring to avoid interrupting mums, sedums and asters that set next year’s flower buds in autumn.
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Transplant overgrown perennials by lifting and replanting the healthiest sections of overcrowded plants.
Use the same planting guidelines outlined above when dividing or moving existing perennials in fall. Water consistently, apply mulch, and give them 4-6 weeks minimum to recover before cold weather arrives.
Overwintering Tender Perennials
While hardy perennials are fine for fall planting, tender varieties like hibiscus and mandevilla need overwintering protection in zones 5 and below. Follow these tips to overwinter them:
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Bring pots inside before temps drop below 50 degrees F to a sunny spot.
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Trim plants back by one-third to one-half to reduce stress.
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Stop fertilizing by September so plants harden off.
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Water minimally just to keep soil slightly moist.
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Move pots periodically to evenly distribute light.
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Keep humidity up by misting and using a humidifier.
With a little care indoors over winter, many tender perennials will survive dormant in pots. Just transition them gradually in spring and fall.
The Benefits of Fall Planting
There are many advantages to putting perennials in the ground in autumn:
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Soil is still warm, encouraging root establishment before frost.
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Cooler temperatures prevent moisture loss and transplant shock.
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Ample fall rain provides the steady moisture vital for new plantings.
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Weed pressure subsides as cooler weather halts weed seed germination.
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New roots have ample time to develop before winter dormancy.
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Nurseries offer end of season discounts on surplus inventory.
By properly timing perennial planting in fall for your zone, you can extend the growing season and prep your garden for next spring. Add new plants, divide existing ones, and fill in empty spaces opened up from summer fade. With the right selection and care, fall planting can boost next year’s garden performance.
Bottom Line
It’s perfectly feasible to plant perennials deep into fall provided you choose suitable plants and give them proper care. Focus on hardy varieties adapted to your climate. Plant them at the right time for your zone and tend to them diligently through fall. With smart preparation, most perennials will flourish when planted in autumn and give you a head start on next year’s garden.
From Seed
Some perennial seeds can be started indoors in early to mid-spring, but seeds that need cold stratification should either be stratified indoors in the fridge in early spring or directly sown outside in late fall so they can naturally cold stratify over winter.
How to Plant Perennials
Most gardeners grow perennials from potted or bareroot plants purchased from garden centers or seed catalogs, but you can also grow most perennials from seed and save money on your garden—as long as you don’t mind waiting a little longer for your plants to bloom.
When is Best time to Plant Perennials in the Garden?
FAQ
How late in the year can you plant perennials?
Perennials can be planted any time of year.
By planting them in the fall, plants will have a long time to establish a strong root system before the hot, dry summer months. In fact, the roots are likely to continue to grow as long as the soil temperature is over 50 degrees Farenheit.
What is the latest you can plant perennials?
Although each plant’s needs may vary and some will be more winter-hardy than others, in general about a month before the last fall frost is sufficient in giving the plant enough time to establish itself and take root.
What month is best to plant perennials?
When to plant perennials. Perennials are best planted in spring (March to early May) or autumn (late September to October), while the ground is moist.
When should I stop planting perennials?
So the rule of thumb for planting perennials is plant from date of average last frost until a month before the first frost. But we can plant woody plants any time the ground isn’t frozen. Why can’t we plant dormant perennials in February when it’s 65 out and the ground is mud?
When is the best time to plant perennials?
The best time to plant perennials is either in the fall, allowing roots to establish before winter, or spring when the soil warms up. Timing ultimately depends on the specific plant and my local climate conditions. In planning for perennial plantings, I focus on the key factors of timing, soil prep, and ongoing care to ensure success.
How do you plant perennials in the fall?
Digging the Hole: Dig a hole that’s about twice as wide and just as deep as the plant’s root ball. This gives the roots plenty of room to spread out, which is what we want in this nice, cool fall weather. Spacing: Make sure to space perennials according to their mature size.
Can you plant perennials late into the season?
This makes your success rate greater when planting perennials late into the season. You can plant hardened-off plants up until the ground freezes. When planting later in the season, be sure to prepare the soil properly depending on the particular plant’s needs.
Is it better to plant perennials in the fall or spring?
In general, fall is a better time to plant perennials. Planting in the fall allows plants time to grow and prepare for the winter. By getting the plants in the ground before it freezes, you give them a chance to grow while the ground is still warm. Planting in the Spring it is the opposite situation.
When should you transplant a perennial plant?
For transplants, plant perennials that flower in spring and early summer in autumn, and perennials that flower in late summer to autumn in spring. This will ensure your plants have time to settle in before their flowering season begins.
When should I plant bare root perennials?
For bare-root perennials, early spring planting gives them a good start, while I plant container-grown perennials in either spring or fall. Once the perennials are in the planting bed, proper watering is crucial, particularly for newly planted perennials. They require consistent moisture to thrive.