Our favorite cool-season annuals to plant this fall
Ah, lovely October. It’s the season for leaf raking, pumpkin picking, cider sipping, and tailgate parties. And, if you’re smart, it’s also the season for planting winter- and spring-blooming annuals. I know, I know: Your “think spring” instinct doesn’t kick in until March. But plant now anyway. Your cool-season annuals will grow stronger and bloom longer than if you wait until spring.
The five annuals described are especially good performers. They’ll pump out flowers nonstop as long as the weather stays cool.
Where winters are cold, plant dianthus, pansies, and poppies now. These hardy annuals will establish roots in fall and winter, then explode into action come spring. (In colder climates, wait until spring to plant the other annuals listed.) Where winters are mild, you can have “spring” flowers in fall and winter too. In addition to the three listed above, you can plant tender annuals like nemesia and stock.
So put down that rake and head to the nursery.
Dianthus: Members of the genus Dianthus, carnations, Chinese pinks, and sweet William are usually grown as annuals. All are cold-hardy and have a long bloom period. Greenhouse-grown carnations reach 3 to 4 ft. tall, but the varieties you find in nurseries usually grow 12 to 14 in. tall. Sweet William is slightly taller ― 20 in. ― and Chinese pinks range from 6 to 30 in. Flowers of all three are pink, red, or white, often with intricate markings in a second shade. Many types have a clovelike scent.
- Plant them in front of blue-flowered catmint, delphinium, foxglove, or salvia.
- Grow them beneath roses in compatible colors.
- Use them to form a ribbon of color in front of low-growing conifers or shrubs.
- Plant them in a window box with stock for twice the spice.
Nemesia: This low, mounding annual blooms so profusely, you barely notice its narrow leaves. The flowers look like small snapdragons and are sometimes lightly scented. In areas with mild winters and summers, nemesia blooms nearly year-round; elsewhere it puts on a strong show until temperatures soar. Blooms come in many colors; pastels predominate, but shades of plum, red, and bright yellow are becoming more common. Plants range from 6 to 16 in. tall; forms vary from compact and upright to loose and cascading.
- Use it to edge mixed borders.
- Plant it among spring-blooming bulbs.
- Grow it around mixed plantings in large containers to soften the pots’ edges. Or plant one of the cascading forms, like Sunsatia Lemon, by itself in a stately urn.
Pansies and violas: These low-growing plants (6 to 10 in. tall) with five-petaled flowers are top sellers year after year for good reason. They deliver lots of blooms over a long period, come in a huge range of colors ― both solids and bicolors ― and bloom through winter in much of the West. The large-flowered, faced varieties may catch your eye first in nurseries. But when planted en masse, nonfaced, single-colored varieties are often more striking. The original wild pansy ― Johnny-Jump-Up ― still charms us too.
LANDSCAPE USES: Their low, mounding habit makes pansies and violas extremely versatile. Use them in mass plantings, along the edges of mixed borders, in rock gardens, along paths, and alone or in combination with other plants in containers.
- Combine blue pansies with orange and yellow Iceland poppies in beds.
- Use yellow and orange violas to edge a bed of leaf lettuce.
- Plant violas as covers for freesias, hyacinths, or sparaxis.
Poppies: With their silky blossoms, poppies are the ultimate show-offs. While some kinds have big, rowdy leaves, making them difficult to use well in small gardens, our favorites ― alpine, Iceland, and Shirley poppies ― are more delicate. Shirley poppies grow 3 ft. tall and produce 2-in.-wide flowers in bright solid colors, bicolors, and pastels. Iceland poppies are shorter (1 to 2 ft. tall); flowers are cream, orange, pink, rose, salmon, yellow, or white. Alpine poppies, which do best in cold climates, are only 5 to 8 in. tall.
- Grow orange Iceland poppies with blue pansies, or pastel Shirley poppies with Antique Shades Sorbet violas.
- Pair salmon Shirley poppies with Apricot Beauty tulips, or rose Iceland poppies with Pink Impression tulips; underplant either combination with forget-me-not flowers.
- Use red poppies like ‘American Legion’ to add sparkle to silvery dusty miller.
Stock: This mainstay of the cut-flower industry is also an excellent spring bedding plant. Many strains of Matthiola incana are available, ranging from less than 1 ft. tall to as much as 3 ft. tall, and from 10 to 16 in. wide. Flowers are single or double, 1 in. wide, and come in a range of colors, including cream, mauve, pink, purple, red, salmon, violet, and white. All have a wonderful spicy-sweet scent. Evening scented stock (M. longipetala bicornis) has an even more powerful scent.
LANDSCAPE USES: Because one of the nicest things about stock is the intense fragrance of its flowers, plant it where you’re most likely to smell it. Combine taller varieties of stock with plants that are looser in habit, such as nemesias, so they don’t look so primly upright.
- Grow stock alone in small pots, as pictured, for portable scent.
- Fill a window box with it.
- Mass it in beds for a showy display and knockout scent.