5 flowers to plant in September – now's the time to ensure a beautiful, blooming backyard

If your flowerbeds and container gardens are looking a little flat and lackluster they need a fast makeover with a boost of instant color. You may think that the growing season is over but the good news is there are plenty of plants you can choose now that will add little bursts of heavenly flowers to see you right through fall.

Late blooming perennials and cold season annuals are the last flowering delights the garden can offer before the onset of winter. Another plus is that their colors tend to be intense and saturated as the sunlight isn't so intense at this time of year. Choose varieties like chrysanthemums and coneflowers and on sunny days the flowers will be covered in pollinators too, busy collecting nectar before winter sets in.

So enjoy September days by getting out in the backyard to do some planting. Now find out which plants to plant in September with our expert-led suggestions to add a little joie de vivre to your outdoor space.

1. Autumn sage (salvia greggii)

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'Fall is an ideal planting season, between September and November,' says Amy Hovis, co-owner of Barton Springs Nursery in Austin, Texas. 'As the weather begins to cool down, there's typically more consistent rainfall, making it a favorable time for establishing plants. We suggest planting native perennials. A few of our favorites are autumn sage (Salvia greggii), lantana, and blackfoot daisy.'

Autumn sage is one of our favorite September plants to see in flower beds too, as it's still flowering prolifically in late summer and fall. It grows rapidly to a mature size of 2 to 3 feet, and loves a hot climate, full sun, and dry soil. It has masses of petite blooms in a range of colors including red, pink, white, violet, peach, and orange, so there's one to suit every color scheme.

Fall planting extends the growing season for plants. This gives them more time to establish strong root systems and gather resources before winter arrives. As a result, they are better equipped to face challenging conditions like heat and drought the following summer.

2. Coneflowers

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'The best plants to plant now depends on where you live,' says Justin Hancock, horticulturalist at Costa Farms, expert perennial growers based in Florida and the Carolinas. 'In Northern regions, early fall is the ideal time to plant most perennials. Planting now allows them to get well rooted before winter so they have a much stronger start in spring. 

'Planting perennial varieties like coneflower (Echinacea), bee balm (Monarda), or phlox now will result in more blooms next year than if you waited to plant the same plant in the spring.'

Long-lasting coneflowers are synonymous with September, as well as being one of the best flowers for bees. They have dusky pinky-purple flowers with a distinctive orange cone at the center. They work well planted in drifts with ornamental grasses and other autumn perennials, and are popular with pollinators too. Grow them in rich, well-drained soil in full sun for a colorful and long-lasting September display.

3. Chrysanthemums

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Choose chrysanthemums this fall if you want an outdoor plant that keeps blooming through rain, wind and snow. When most other flowering plants have already died back ‘mums’ are one of the best flowers for adding a welcome pop of color during the fall months. They are a great late season pollinator plant too.

'It's not too late to plant and enjoy fall-flowering perennials like chrysanthemums, as well as asters, sedums, and Montauk daisy, which all look good now, go dormant, and will come back to provide more flowers next fall in your landscape,' says Justin Hancock. They may last right through too if you live in a warm climate or the winter is a mild one.

We love all chrysanthemums but particularly the 'Reflex' flower form ones, which have full blooms that can grow up to 6 inches in diameter, and graceful petals that curve downwards. If you love pink and purple fall flowers, plant one of the pretty pink varieties of these chrysanthemums together with asters, coneflowers and stonecrop for a soft autumn palette that looks stunning in the September garden.

4. Pansies

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As temperatures cool, September is a great time to incorporate cool-season annuals for a fall/winter color splash in your yard or planters.

'I am currently planting some staple fall flowers in my garden,' says Alex Kantor, owner of Perfect Plants Nursery in Monticello, Florida. 'As well as zinnias and chrysanthemums, I'm planting lots of pansies. These plants are classic favorites for the fall season. September is an ideal time to plant them, as the soil temperature and texture are perfect for establishing their roots.'

These cool weather-loving plants will display their vibrant colors and blooms throughout the fall. While they can be treated as perennials in some areas, they are mostly used as annuals. 

Choose your favorite colors and tuck them into flowerbeds and planters. 'The wide variety of pansies never ceases to amaze me, making them a delightful choice for September planting,' says Alex. 'Playing with their colors in the garden adds a touch of alluring charm you can enjoy before winter arrives.'

5. Ornamental brassicas

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While chrysanthemums and pansies are generally the predominant plants for seasonal color in the fall garden, showy ornamental cabbage and kale varieties are great for replacing faded summer annuals for a long-lasting fall display. 

'I have been experimenting with planting ornamental brassicas as a border in my garden,' says Alex Kantor. 'This gorgeous cabbage can be used in flowerbeds, in pots, or even in small gardens to give your landscape a unique touch. The deep green edges of these perennial rose-shaped plants will gradually unfurl to reveal a center of vibrant purple and magenta throughout the season.'

These showy plants are grown for their large rosettes of colorful leaves, and come in a variety of colors, including pinks, purples and reds. The fancy ruffled leaves won’t have much color until it gets cool though, and really begin to blaze after frost and cold weather, getting more vivid colors below 50°F. They really are cool-weather plants, and once acclimated last well into November and December. 

The plants will generally not get much bigger after planting them out so be sure to buy decent sized ones for the best effect. Use them in mass plantings in flowerbeds, or to edge paths. They look beautiful in the front of a flowerbed combined with sedums and asters. Alternatively make them the centerpiece in a fall container garden with pansies planted around the edge for a long lasting display.