You might not think it, but the fall months of October and September are prime time for many perennial garden tasks. While we think of perennial gardens as highlights of spring and summer, they shine in the fall, too, if they have the right plants. But there is work to do beyond planting for decoration. A bit of work in October can set your perennial garden up for a truly stellar spring.
What should you take on in your perennial garden in October? Here are our top ten suggestions.
- Top 10 Things to Do in Perennial Gardens in October
- 1. Get in some last plants of color.
- 2. Attack pests (slugs in particular)
- 3. Order or buy fall bulbs
- 4. Plan planting time for fall bulbs
- 5. Plant fall bulbs
- 6. Hit the clearance sales
- 7. Divide older and overgrown perennials
- 8. Move and rearrange plants
- 9. Prep your beds (Mulch and Amend)
- 10. Save some seeds (or leave some for the birds)
- Bonus Tip for Fall Perennial Gardening: Know Your Zone
Top 10 Things to Do in Perennial Gardens in October
1. Get in some last plants of color.
There are still some plants that can grow through the first frosts until a hard freeze hits. Put some of these plants in now so you can continue to enjoy bright colors. Planting some hardy flowering perennials in the ground in late September or early October can give you a month or more of flowers in fall tones. Even if you only get three or four weeks out of these plants, it’s worth the looks and time enjoying these final fall flowers before the long winter.
Of course, how long your plants last, how long they flower, and how long they hold their foliage will depend on where you live and how long the regular hard frosts hold off. In a lot of places, given the changes in the seasons and the weather patterns, you can enjoy your fall plants for longer than you have in the past—frosts and cold weather are coming later and later in a lot of places. You may not want to count on that happening, but if it does, it’s a bonus for you.
To get the longest life out of your fall gardens and fall perennials, be prepared with covers and season extenders. If you cover plants well (cloth-like covers and frost blankets are the best things to use), you can usually get your plants to live through most of the month of October and through the first several fall frosts.
Some of these plants will survive in a dormant state through the winter and will come back in the following year. Hardy mums will often do this, even though we tend to treat them more as annual plants that we replace.
If you plant mums in the ground like you do other perennials, they may overwinter. They’ll send up new green growth in the spring and summer, then work towards flowering in the fall. This doesn’t always work, but it’s well worth a try if you’d only be tossing the potted plants anyway. (I’ve even had potted hanging mums overwinter in an unheated greenhouse and revive for the coming year. Just don’t let them dry out completely.)
You don’t have time to start things from seed if you want to enjoy them in your fall garden because perennials and flowers are slow growers, and the temperature won’t be right for most germination and growth. Transplant well-established, showy plants from a nursery or garden center. Choose plants in flower or ready to open, not those that are already spent.
Also, consider foliage plants and ornamental cole crop plants. These last a very long time (even through some serious freezes) and will keep life and muted fall colors alive in your autumn garden beds.
Other hardy fall flowers and perennials that are worth planting in October include:
*Plants noted with an asterisk are hardy annuals. Though they won’t typically survive winter, they are perfect companions in the fall perennial garden, as they’ll usually outlast the perennial flowers and almost surely will if they are covered when frost is predicted.
- Ornamental kale*
- Ornamental cabbage*
- Potted asters
- Rudbeckia (Black eyed Susans)
- Montauk daisies
Of course, anything that you can put in the ground can also be grown as a container garden plant. You can often keep these going even longer because when frost or freeze hits, they can come inside for the night, and then you can put them back out during the warm days.
2. Attack pests (slugs in particular)
Slugs are still feeding, and they will be more of a problem as the days cool and the available foliage becomes less. When they run out of leaves to eat, they will start to burrow down in the ground and attack plant roots. Hostas are a favorite, and they will love to find those fresh fall transplants of ornamental cabbage and kale with all their fresh greens to eat.
Not only are slugs a big problem in the fall perennial garden, but if you don’t put them in check before they go dormant for the winter, you’re encouraging a spring slug explosion—primed and ready, waiting in your perennial beds.
Act now to kill slugs. Put out beer traps or other slug traps or baits.
If you see other worms, caterpillars, or feeding insects eating your perennials and annuals in your beds, use an organic spray, neem oil, or organic powder to kill them. It’s best to control feeding pests when you see them so that this year’s small or irritating population doesn’t explode into something unmanageable next year.
Keep in mind that as the season progresses, natural predators like birds and carnivorous insects will be migrating and going into hibernation or dormancy, so you may not have as much help from Mother Nature at this time of year. Take some time to keep problem pests in check.
3. Order or buy fall bulbs
The earlier you order or buy, the better your selection will be. If you are ordering, leave yourself some extra time for shipping so you get your fall bulbs in plenty of time for planting in the ground.
You’re sure to find bins of fall bulbs at your local garden center or home improvement store, but the options here are often plain, common, and limited. There are some excellent options out there for fancier, unique types of spring flowering bulbs to plant in the fall for spring color and early blooms.
Don’t limit yourself to just what’s on the store shelves. Check out some fancier options like double daffodils, colored other-than-yellow daffodils, daffodils with uncommon flower shapes, and peony tulips.
4. Plan planting time for fall bulbs
Make a plan to get your spring bulbs in the ground in October before the ground freezes. Put it on your calendar. Set the time aside.
If you miss the fall planting window, you’ll set yourself back a year, and spring flowering bulbs (like daffodils, tulips, etc.) will not bloom in the spring. So, get it on the schedule and make it happen this month.
5. Plant fall bulbs
Fall is the time to plant spring flowering bulbs. When we say “spring flowering bulbs”, keep in mind that this refers to bulbs that need a cold period in the ground over the winter and that will bloom in early to late spring. This does not mean that you should put bulbs that are not cold-hardy in the ground; those are more commonly considered summer flowering bulbs.
For example, don’t plant gladiolus in the fall or dahlia tubers. These are flowers that should be planted when the ground has warmed in the spring and when the danger of frost has passed (unless you live in a zone where they can overwinter without dying).
You do want to get things like daffodils, hyacinths, snowdrops, alliums, and daffodils in the ground in the fall if you want them to bloom in the spring. These will mostly come back year after year as perennials if you leave them in the ground (some varieties of these, especially fancier varieties of tulips, may only last a year or two as perennials, so it’s often a good idea to add to tulip plantings to refresh the patch to be sure you have some coming up in the spring).
These hardy bulbs will generally survive if they are planted at any time while the ground is workable, but they’ll do better if planted when the ground temperature is consistently in the 40-to-50-degree Fahrenheit range. This usually happens when nighttime temperatures stay in the 40s to 50s (4.5 to 10 C), which is about a month before the first frost or two months before you expect your first hard freeze.
6. Hit the clearance sales
Garden centers don’t want to deal with plants over the winter. It’s too much to store and to maintain (even though the maintenance is minimal for overwintering plants, it’s a lot of space that’s needed for other stock).
BUT. October is a great time for planting all sorts of perennials. These perennials are much better off in the ground, where they can heel in and be ready to grow in the early spring. Their roots have better protection in the ground than in pots. So even though your garden and landscape center may be done with dealing with potted perennials, you shouldn’t be.
This is an excellent time of year to grab great deals on perennials of all sorts, including trees, shrubs, berry plants and bushes, and perennial edible plants like rhubarb. If you can find it and it looks like there’s life left in it—even just dormant life—buy it at great savings and get it in the ground.
7. Divide older and overgrown perennials
Early October is a good time to divide fall perennials. Aim for early in the month while you have a month or more before a hard freeze. This will give your newly divided perennials time to let their roots establish a bit before the ground freezes and they go completely dormant.
Perennials that are becoming overgrown or overcrowded should be divided. This will refresh the look and the order in your perennial garden. Dividing perennials every three to five years will also stop them from becoming root-bound, which chokes plants and results in fewer blossoms, anemic growth, and smaller, less attractive plants. A simple division can breed loads of new life into perennial plants.
The divided halves and sections that you remove can be planted elsewhere to expand your perennial garden, or they can be sold, given away, or potted to be planted later (but potting may require overwintering somewhere).
Not sure what to divide? Check out these 15 Perennials to Divide in Fall
8. Move and rearrange plants
Fall is the best time to move and rearrange plants and garden arrangements that aren’t working for you. October is a great time to do it.
In the fall, the look, feel, and performance of your seasonal garden is fresh in your mind. You’re much more likely to remember what bothered you in the spring and summer now. If you wait for next spring, you will probably have to wait for the plants to break dormancy, and by then, you may be well into late spring and summer heat—not the ideal times to transplant perennials or stress them by cutting their roots.
Just like transplanting dormant and potted plants, fall is a good time for transplanting perennials from one area of the garden to another. The plants will be set for the spring and ready to take off. You’ll enjoy having your spring perennial garden set to take off, ready to look its best next season.
9. Prep your beds (Mulch and Amend)
Amending soil in the fall ensures that nutrients are in place in the spring when they are needed. This makes nutrients available to plants when they begin to grow (which starts earlier than we often realize and may not be noticeable at first).
October is a great time to put nutrients back that were depleted over the summer growing season. Getting compost, leaf mulch, and other organic matter back in your garden beds gives them time to break down and work into the soil over the course of the winter.
Think of it as having breakfast in bed for your perennial garden—instead of waking up shaky and starving and then having to work for your food, which may not even be there to find!
After you amend your soil, add a layer of mulch. Mulch acts as insulation for roots and the crowns of perennial plants. This prevents winter kill and reduces heaving, which often causes perennials to be pushed out and potentially killed by frost expansion and contraction. Heaving also results in dried-out roots, killing the plant from dehydration.
Fall mulches can be yard waste and leaf litter, which break down into lovely organic matter to feed the soil, or they can be things like bark mulch for a more finished look. They can even be layers or combinations of the two (just don’t make the total amount of mulch too thick—not more than three or four inches). If you use a dressed-up bark mulch in the spring, you will only need to add a light layer to freshen up the look of your perennial bed.
10. Save some seeds (or leave some for the birds)
If you walk around your gardens and flower beds in October, you’ll find a lot of brown, dried seed heads left. These are perfect for seed saving. They’ve run through their life cycle and dried naturally. All you have to do is collect them, separate them from dead matter, and save them in an envelope in a cool, dry place until you’re ready to plant them.
You can grow an almost endless supply of perennials this way and expand your plantings with more of your favorite plants and flowers. You can save these seeds to plant in the ground after the spring thaw, or you can start them indoors this winter and have them ready to plant out as transplants when the time is right for spring transplanting.
Bonus Tip for Fall Perennial Gardening: Know Your Zone
As you look to planting and tending your perennial garden this October, take a minute to find out what zone you are in.
Your gardening or hardiness zone is a measure of the climate you live in. It takes into account how low your temperature goes and how long your ground is frozen or exposed to different levels of cold. Different perennials have different tolerances for cold and low temperatures and different periods of cold that they can survive.
Knowing your zone will tell you which plants can be grown where you live, which can survive year to year as perennials, and which cannot. This is the one most crucial piece of information for the successful perennial gardener.
Perennials are typically more costly plants, but they are worth the money because they come back year after year. Perennials reduce your planting and maintenance time greatly—but only if you are planting appropriately hardy perennials for where you grow.
So, before you grow, get in the know. Know your gardening zone so that when you are ordering, shopping the sales, and selecting plants and bulbs, you are putting your time and money into perennials that can grow and thrive where you are.
Time spent in the perennial garden in October is time well spent. Your beds will reward you with strong, healthy growth in the spring and well-arranged gardens that are ready to shine. You’ll find that taking the time now when you have more time to give will also ease the workload in the spring and have your yard and gardens looking all the better for it.
Happy October perennial gardening!