Posted on Apr 01, 2017 | by Kerry K
Well, keep your shorts on, or in this case, your long johns, and take comfort in the fact that you don't have to starve yourself until after the last frost. Although your main entree may be a few weeks away, you can still nibble on some cold hors d'oeuvres until dinner is served. Cold and frost tolerant annuals and vegetables will give you plenty of ingredients to mix and match in your beds or containers.
Most popular on our early spring menu are pansies and violas. In a vast array of colors, with or without their famous patterned “face,” these are the workhorses of the spring garden. Tolerating below freezing temperatures, nothing brightens a border like a bold ribbon of pansies in solid or contrasting hues. They are equally charming as an underplanting for spring bulbs or deciduous shrubs. Showy large-flowered pansies still have the edge in sales, but savvy gardeners are starting to realize the advantages of the smaller-flowered, yet equally impactful violas. The individual blooms of viola may be less grand, but the far greater number of flowers more than make up for their comparatively diminutive size. They are generally more temperature tolerant than pansies, which results in improved performance during colder weather, and extended blooming into warmer months. New breeding has given us improved habits—compact spreading plants that cover larger areas. They also re-seed easier than pansies.
If you love pansies, but don't enjoy sharing them with hungry deer, then perhaps stately snapdragons are more your style. In almost as many colors as pansies, snaps are traditionally cold-tolerant, and some newer varieties will bloom into the summer as well. Garden centers will offer mostly compact plants that reach 15 inches or less, perfect for containers, or hanging baskets of gently trailing varieties. Since these elegant beauties make such great cut flowers, if you aren't lucky enough to find old-fashioned tall cutting varieties like “Rocket” in the annuals section, you may want to grow them from seed. Either way, you'll have a spectacular show that doesn't appeal to your local Bambis.
Two other cool-weather annuals related to snapdragons are nemesia and diascia (photo below). These have similar, but smaller, flowers than snaps, and are more mounding to trailing in habit. Nemesias bloom in mostly pastel hues of pink, blue, or white, while diascias comprise a bolder palette of red, deep pink, and orange. Both add a desirable delicate texture to container plantings, contrasting well with larger flowered pansies. As temperatures heat up, cut these back if blooming wanes to encourage re-flowering later in the season, and to discourage legginess.
Daisies are always a favorite, and no daisy-shaped blossoms are as vibrant or spectacularly colored as pericalllis and osteospermum. Terrible names, but fabulous flowers! Both prefer cooler weather, and benefit from cutting back in the heat of summer. Pericallis is a hardier relative of the florist's cineraria, with the same attractive compact, rounded habit and basic color range. But even the bright hues of cineraria pale in comparison to the positively electric glow of pericallis, in vibrant blues or magenta. These will perform best in part to full sun and consistently moist, but not wet, soil.
For drier, sunnier sites, osteospermum is your best bet. Most osteo varieties, whether yellow, orange, copper, purple, burgudy, or white, will have a central disc surrounded by a ring of intense bluish-purple. The “Voltage” series, although lacking that feature, is notable for its exceptional heat tolerance, blooming right through spring, summer and into fall, as long as plants are deadheaded.
Other frost tolerant annuals to look for are argyranthemum, lobelia, petunia, million bells, mimulus, schizanthus, ranunculus, verbena, calendula, godetia, and fragrant sweet peas, stock, and dianthus. Good early biennials and perennials include primrose, wallflower, English daisy, iceland poppies, creeping jenny, heuchera, and euphorbia.
Cooler weather also suits many vegetable plants, such as peas, broccoli, kale, spinach, Swiss chard, and lettuce. The latter two add a unique touch to container plantings. The hot pink, yellow, red, and orange stems of “Bright Lights” Swiss chard add height and interest planted with pansies and sweet alyssum.
Lettuces are a great container accent plant—try colorful varieties like “Simpson's Elite” (chartreuse), or “Red Sails” (burgundy). As an added benefit, you can still eat them--if larger leaves are picked first and young leaves left to grow, continued harvests are possible and your container will still look great!
Once you've made your choices, a few simple guidelines will help ensure your success.
- First, cold-acclimated plants will withstand lower temperatures. When buying, ask about frost tolerance—any reputable garden center should know whether their annuals have been grown in a warm or cool greenhouse (or outdoor grown, as is the case with many perennials), and how long they've already been outside.
- If you need to acclimate them yourself, start with a day above 40 degrees. Place them in a semi-shady spot out of the wind, and bring inside when temperatures may drop below 40. After a few days, cold-tolerant annuals should be able to survive a light frost or freeze, when temperatures may drop as low as 28 for several hours. If colder temperatures are predicted, or you just want to play it safe but can't bring plants inside, cover them to the ground with commercial frost cloth, old bed sheets, boxes, buckets, flower pots, or plastic jugs with the bottoms cut out. Remove the covering in the morning when temperatures rise above freezing. Try not to use plastic—it traps moisture which may then freeze on the plants.
- Remember to keep plants properly watered, but do not heavily water lettuce before a freeze, as the plant cells will absorb the extra water and suffer freeze damage as cells burst.
So, if the winter-spring weather roller coaster gets you down, don't despair! If you choose your plants carefully, and pay a little extra attention to the weather report, you can get your garden rolling sooner rather than later.