No matter how carefully I plan, no matter how perfect the growing conditions, it’s inevitable that I find gaps in the garden in late summer. Clearly, I’m not alone, or there wouldn’t be such a market for potted mums in September. Thing is, it’s tough to find holes exactly the right size for big potted fillers, and the dense, mounded form of container-grown mums make it hard to have them look loose and comfortable, instead of like blobs dropped into the garden. With a little advance planning, annuals can be a much better-looking option for filling spaces and adding fall color.
I’ve found that early to mid-August is the ideal time to give the garden a thorough grooming and then tuck annuals into the holes left by weeding and cutting-back. The only way to have fresh-looking fillers on hand at this time is to start them myself in July. And now that I’ve gotten more into vegetable gardening, it’s easy to think about starting annuals at the same time I’m sowing kohlrabi, broccoli, cabbage, lettuces, and other veggies for fall.
I used to just start whatever seeds I had left over from spring, and I still do that to some extent. But I also like to look for good sales in early to midsummer, when retailers are trying to clear out their spring seed racks. Even better are the fillers that I can easily root from cuttings of plants I already have. Set out in late summer, the seedlings or rooted cuttings have a few weeks to settle in and mingle with their companions, adding a lusher look to the garden.
So, what makes for good fall fillers?
For one, they have to sprout (or take root) and look good quickly. Started in pots in early July, purple basils such as ‘Red Rubin’, ‘Osmin’, and ‘Purple Tulsi’ are one of my favorites for August and September color.
The down side is that they’re very cold-sensitive, so they look pretty scrappy as soon as nights get chilly.
Coleus (Solenostemon), such as ‘Oxblood’ (above) and ‘Sedona’ (below), are also great for fall foliage color. In just two weeks, cuttings can root and produce a nice-sized filler plant for the front to middle of a border.
The same goes for ‘Purple Lady’ beefsteak plant (Iresine) [above], though it’s more of an spreader than an upright grower. That makes it ideal for sprucing up the edge of a border.
Sweet potato vines (Ipomoea batatas) root even more quickly than coleus and beefsteak plant. In fact, I often find pieces that have already taken root in my bark-mulched paths when I trim back some of the over-enthusiastic patches in August. If the weather is going to be cloudy for a few days, I transplant them directly to fill bare spots; otherwise, I put them in pots for a week or so before planting them out.
It takes them several weeks to thicken up and start vining again, so they’re not ideal for filling in along the front of a border (unless maybe you plant several cuttings in each pot to create a thicker clump). They are terrific for filling in around the base of upright perennials that have lost their lower leaves, or that have needed to be cut back.
‘Homestead Purple’ verbena is another trailing filler that’s super-easy to propagate from cuttings, or from stems that have rooted where they touch the ground.
Wandering jews (Tradescantia zebrina) are even easier than sweet potato vines: I just snip off shoot tips a few inches long, scratch up the soil a bit in a new spot, and keep the soil moist for a few days to let them root. They’re much more diminutive than sweet potatoes, so they’re ideal for small spots. I found one this spring that’s a solid deep purple, but the silver-and-green, white-and-green, and white-, pink-and-green ones are equally pretty and just as easy to propagate.
Most of the fillers I use for fall are low-growing trailers and weavers, but some of them are a bit taller for height or bulk. Cosmos – both Cosmos bipinnatus and C. sulphureus types – are ideal for this, easily reaching at least 2 to 3 feet in fall from a mid-July sowing and mid-August transplanting.
‘Tiger Cub’ corn (Zea mays) also reaches about 2 feet tall, and it has showy, white-striped foliage. It’s a simple matter to direct-sow the kernels in early to mid-July and enjoy the clumps of strappy foliage through September.
I have one tough spot in the front garden where a species peony fills a space about 3 feet across until mid-August, when it suddenly turns brown and goes dormant, leaving a huge empty space by late August. This year, I solved the problem by starting bed-of-nails (Solanum quitoense) from seed in early July, cutting back the other stems of the peony, and then setting out the solanum seedlings around the edge of the clump. They grew quickly and filled the space just as the remaining peony stems died back.
So, fast-growing is good when it comes to fall fillers, but it’s even better when they’re plants that actually thrive in cooler temperatures. That way, they just keep getting better as the autumn progresses, even if we get an early light frost.
Nasturtiums (Tropaeolum majus) are one of my top favorites for fall fillers. This year I sowed two flats (36 pots) of various nasturtiums in mid-July and could have easily used twice as many. Planted out in mid-August, they’re looking lush and lovely now in late August and are beginning to flower. They look much better than the ones I’d set out in spring, because those plants really fried during our hot, dry spells.
Pot marigolds (Calendula officinalis) are also winners for the same reasons: they’re super-easy to start from seed, grow quickly, come into bloom when still fairly young, and keep flowering freely as the weather gets colder.
While I’m sowing seeds for the vegetable garden, it’s a simple matter to sow extra chards (such as the ‘Bright Lights’ seedling above) and lettuces for fillers in the ornamental borders, too.
Best of all, though, are the annuals that serve as fall fillers all on their own, with no extra work on my part.
Just when I think I’ve lost them, seedlings of my favorite green flowering tobacco (Nicotiana ‘Ondra’s Green Mix’) start appearing throughout my borders in late July through August.
‘Cramer’s Plum’ love-in-a-mist (Nigella damascena) is another dependable self-sower. The seeds that overwinter sprout early, producing their white flowers mostly in May, followed by the plum-purple seedpods. In July, I crumble the dried seedpods around the garden, and by mid-August, a new batch of seedlings appears for fall color.
A few other self-sowers that help to spruce up the fall garden include dill (Anethum graveolens)…
…borage (Borago officinalis)…
…Brazilian vervain (Verbena bonariensis)…
…‘Kingwood Gold’ jewels-of-Opar (Talinum paniculatum)…
…silver ponyfoot (Dichondra argentea ‘Silver Falls’)…
…sunflowers (Helianthus annuus)…
…and celosias (which often produce some really wild-looking offspring).
Wow, that’s a lot of options for fall color! Who needs perennials, anyway?
I planted some begonias for a little fall color. They are about the only thing blooming in the garden right now. I know they aren’t a popular plant but they certainly are reliable.
I too like begonias, but they don’t like me. I enjoy seeing them in Mom’s garden, though; apparently they like her as much as they like you. Whatever works is fair game!
-Nan
Fabulous! I was just noticing all the bare spots in the garden where I have cut back earlier blooming flowers. I admire the look you’ve achieved but it’s probably too labor intensive for me. I like fall self-sowers – like cosmos, cleomes, red amaranthus and verbena bonariensis. Your green nicotiana are intriguing, and I read your other post on flowering nicotianas to get some history of “Ondra’s green mix.”
Hey, Brenda. You’re right that it’s not a low-maintenance approach, but I really enjoy having an excuse to start seeds and plant with cuttings during the summer. If I were propagating perennials instead of annuals, I’d end up having to start a nursery again!
-Nan
Hi Nancy,
I don’t have a garden blog, I’m a costumer and only lately an almost full-time gardener, now in my 8th season.
I follow your blog, Gardening Gone Wild and have most of your books.
I just have to say this, what I love about your gardening most, is that you’re not afraid to PAINT!
And play.
For the North East, I’ve found that rare, unless perhaps my views on painting and playing are too narrow, or I’ve missed something out there.
I find your plant combinations consistently exciting, joyful and affirmative. I’m glad you’re writing books and being visible. Thank you!
Wow, Lena, what a lovely comment. I’ve had more pure fun with the garden this year than any other season I can remember, even with the appalling heat and drought. I hope you’ll consider starting your own blog to share your gardening adventures.
-Nan
I never thought of filling in holes in the garden. They have always been, well, just holes. Your gardens look beautiful. I’ll certainly be thinking about it next year – and maybe even this year. Thanks!
I wish I had been organized enough to do this post earlier in the summer, Marie; it would have been more useful then. But really, I didn’t realize how important fillers would be this year. I usually don’t have nearly so many empty spaces to fill.
-Nan
Always wonderfully inspiring over your way! :-) I need to work on “fillers” a bit more. Have a great day!
Thanks, Shady! Always glad to inspire.
-Nan
One thing I have noticed is that between the end of July and now the light has changed so much–so that the holes that appear often have completely different light availability than the same locations had in spring (no leaves) or summer (direct overhead light). Thus, some of these great suggestions may not always thrive in the holes. I have had some success in using plants that previously had graced ooutdoor tables or were on the shaded porch to fill in holes. In particular, angel wing begonias and sansaveria like an outing to the yard from now until the frost in semi-shaded areas. They can completely change the appearance of an area for while.
Dan
Good point, Dan; that’s a great idea for many gardeners. Here, most of the garden is in sun from dawn to dusk, so even holes that are shaded somewhat by now-taller plants still get enough light to support full-sun plants. So, none of the fillers I mention here are theoretical suggestions; they’re the plants I have luck with, and that I’ve photographed here.
-Nan
Each of them are beautiful–I wish I had more sun (at least at times like this.) I am particularly delighted with the Silverpony foot. What a wonderful plant.
Dan
I’d be thrilled to trade you some sun for some shade, Dan. Maybe then I could indulge in some begonias too. I’ve also been thinking how cool sansevierias must look in a garden setting. I think you need a blog too!
-Nan
-Nan
I’m going to have to remember this for next year, although I could do the cuttings from the sweet potato vine and the coleus. How long they last outside depends on the weather – 2 weeks or 2 months.
Yep, the way things have been going with the weather this year, I wouldn’t be surprised if we got zapped by an extra-early frost. It’s always a gamble.
-Nan
You’ve given beautiful examples to use to fill the gaps.
Our temps are to hit 99 again today. We’ve had 78 days (I think) of temperatures over 90 this summer. I’ve failed at plugging the holes this year as I can’t keep the shade/watering on the small filler plants. And, the rabbits are taking down my 4 foot high zinnias and cosmos like lumberjacks! Right in front of my eyes, too! My deer are so much better behaved!
I’ve got the summertime gardener blues. I think I need to move to a cooler zone!
It sure has been a rough season, hasn’t it? Maybe we both need to move! But then we’d trade one set or problems for another, I’m sure. I guess we’d better just try to survive this year and look forward to next year.
-Nan
Great ideas. The plants may change for different regions, but the overall lesson is a valuable one, not to give up on late summer in the garden. I’ve taken the sweet potato out of containers and have started to let it spill in front of the border too, where it’s fairly drought tolerant. I think I first noticed it in the border in an article on Montrose. Really gives a lush look.
That’s a good point, Denise – once they’re established, the sweet potato vines don’t seem to need much water, and they certainly love the heat. Unfortunately, voles also love eating the roots!
-Nan
Just want you to know how much we enjoy your blog! It’s so much fun to compare gardening in PA vs the Nebraska prairie!!!!! Hugs to you from a fellow gardener!!!!!!! Sue
Thanks, Sue! From what I’ve seen on other Nebraska blogs, we enjoy many of the same great plants. How fun that we can share with each other!
-Nan
Hi Nan, what an idea packed post! Thanks for all those tips about when to start things for that end of July doldrum period. I like the ones you can just stick in ground. Chard is such a beautiful plant, that is the perfect pick me up to take us into winter.
Frances
That’s one of my favorites too, Frances, because it just keeps getting better through the cool weather.
-Nan
You’re right, that’s a whole lot of options! I really need to do that in my own garden. Such great ideas. I especially should remember coleus as they do so well here. And they’re so easy to take cuttings of!
You’re right, Jean – they’re so easy from cuttings, and you get good-sized plants much more quickly that way. And, you know exactly what you’re getting color-wise.
-Nan
Great idea-packed post, Nan. I love the coleus with iresine and other dark-leaved fillers. Nasturtiums are wonderful, and the Homestead Verbena…and so many others. I plant a lot of annuals late…not because of good planning, but because it takes me a while to clean up and clear spaces for them! I could sure use a garden helper!
But it does make for a colorful fall garden.
I’m loving the annual asters I planted in the Lily Garden – bright pinks and soft purples with yellow centers. They self-sow nicely too.
Wow, thanks for the reminder, Kerri: I haven’t tried annual asters for many, many years. I think they’ll be on my list of fillers to try for next year.
-Nan