Although each plant's needs may vary and some will be more winter-hardy than others, in general about a month before the last fall frost is sufficient in giving the plant enough time to establish itself and take root.
Frost Tolerant Perennials
Those that are frost tolerant can be planted 2-3 weeks before before the last spring frost to give you some immediate color and interest in your gardens or containers. Be aware though, that they may need to be acclimated to the cold weather.
Perennials that are frost tolerant can be planted 2 to 3 weeks before the last frost date for an immediate spring bloom.
The newly emerged growth of most perennials can tolerate temperatures in the low 30s and upper 20s Fahrenheit. Freeze damage may occur if temperatures drop into the lower 20s or teens. Most well-established perennials that have been damaged by freezing temperatures should survive.
Certain cold-hardy plants can survive a light or moderate frost and prosper even if spring temperatures have not quite stabilized. These plants can thrive in cold soil temperatures, compared to their later season counterparts which need a warmer growing medium.
A List of Plants That Can Be Planted Before Your Last Frost Date. Here are planting guides for my absolute favorites on this list: arugula, cilantro, kale, radishes, sugar snap peas, and spinach. Don't forget to add some cold-hardy flowers like pansies or snapdragons in your garden to attract pollinators for your peas.
Now, it's bad to jump the gun and plant warm weather crops early, but you don't have to wait until the last frost to plant your garden! There are a lot of cool weather vegetables you can plant out before your last frost date. So, as soon as your can work your soil, get out there and start planting!
Bulbs and perennials emerging from the ground do not need to be protected from sub-freezing temperatures. They are growing according to nature's schedule. You don't need to protect plants until after we've had an extended warm period.
Perennials can be planted any time of year.
By planting them in the fall, plants will have a long time to establish a strong root system before the hot, dry summer months. In fact, the roots are likely to continue to grow as long as the soil temperature is over 50 degrees Farenheit.
Cover plants with cloth; bed sheets and towels work great. If possible, drape the cloth all the way to the ground and secure. Newspaper and straw can also be used.
Whether your garden goals for the year include a vegetable garden, a perennial herb garden, or general landscaping ideas around your porch, patio, pergola, or pool, April is the time to start planting.
Information On Individual Perennial Species. Planting depth: Plant so that the top of the root is 1" below the soil line. Planting depth: Crown of plant should rest just at or above the soil surface after watering in.
Autumn is the best time to plant hydrangeas, followed by spring planting. Plan to plant in the spring after the last frost or in the fall before the first frost.
Thoroughly Water plants if it's not going to rain before the freezing temperatures arrive. It may sound illogical. However, a moist ground stays warmer than dry soil. Watering the night before the freeze comes will insulate the root structure of the grass and plants and decreases the potential for cold injury.
Frost zaps many perennials back to the ground. Plants are busy storing sugars and other nutrients in their roots to sustain them through winter. To support plants through this season of transition, make sure they get adequate water until the ground freezes.
Some Hardy Perennials Need Winter Protection in the North and Midwest, and Tender Perennials Require Special Protection Methods. Many perennials hardy for your zone make it through winter just fine with no special attention.
Planting. Most perennials should be planted in the fall or early spring. Fall planting gives the plant more time to become established before the start of active growth in the spring. Fall-planted perennials are usually well-established before hot weather.
Spring-blooming perennials, especially in the bare root form, are best planted early in the fall. Planting in the fall while the soil is still warm will give the roots enough time establish properly. This allows the plants to emerge from well established roots, with a stronger start, the following spring.
Most perennials will pop through the mulch in spring. If the plants are young, small, or newly planted in fall, you may need to clear some of the mulch in spring so that the plants can emerge without difficulty through the winter protection.
When Should You Cover Plants? Cover your plants at night and remove them during the day when the temperatures rise above 32 degrees F, so that the soil can warm up again. Some outdoor plants won't survive the harsh conditions of winter, bring them inside and use these tips for caring for them through winter.
A covered porch usually provides protection from light frost, but the garage or sun room is better for freezing temperatures. A couple days in darkness won't hurt the plant. Or move them out during the day and back in at night, if cold temperatures persist.
Know Your Plants' Cold Tolerance
Some frost-tender plants need to be covered as soon as the temperature hits 32°F, while others can handle lower temperatures and/or longer freezing periods. You'll need to look up each of your plants to verify its cold tolerance.
If the first frost is quickly approaching, quick-maturing plants are best, like arugula, bok choy, spinach, radishes, and turnips. You'll be able to get a good harvest before the cold kills them off. If you have less than two months before that first cold night, beets and radishes are your best bet.
To protect plants from frost, you will need to cover them to keep the moisture from freezing. While an unexpected frost can leave many gardeners scrambling to find anything to cover their tender plants; it is important to use the right materials.