As you may have already guessed, you need to pay very close attention to your local weather in the spring. Specifically, you are going to need to watch when the last frost occurs. In general, when there hasn't been a frost for two weeks, you are SAFE to plant your spring flowers outside in Massachusetts!
When soil warms to about 65°F (about two to three weeks before frost-free date), cool tolerant plants can be planted, such as nemesia, diascia, snapdragons, alyssum, osteospermum, mimulus, lobelia and petunias. Most potted perennials that have been acclimated can also be planted at this time.
Most flowers should be planted after your region's last frost date. Planting flowers in spring is the most popular time, but perennials do fine if planted in early fall in the North and late fall in the South.
The best month to plant flowers in spring is really down to the USDA hardiness zone you live in and the likely last frost date. This is likely to be from around March, but if you live in a northern zone, be sure to plant frost-tolerant perennials until you are happy that the risk to more tender flowers has passed.
Black-Eyed Susans are the perfect flower that can be planted anywhere in your yard, garden, and even inside your house for all year summer blooms. While they thrive in gardens they also do well in compacted soil or in mulched areas of your yard.
Vegetables such as potatoes, carrots, peas, radishes, cauliflower and lettuce are all hardy in cool spring conditions and can be planted in March. To elongate the harvest, stagger plantings so the veggies will mature at different times.
Perennials to plant in March
Summer and fall bloomers can be lifted and divided now. Daylilies, chrysanthemums, hostas, daisies, and coreopsis are easy to divide and transplant when still semi-dormant.
Gardening in the fall provides a longer period with more 'good' days, as compared to the often tumultuous spring season. Plus, if you plant in fall you'll end up ahead of the game and won't have to rush to get everything done after winter. In fact, a good strategy is to plant perennials when you plant your fall bulbs.
April is a great time to plant many types of flowers. Some of the best choices include pansies, petunias, snapdragons, and lilies. Pansies are ideal for cooler climates as they can tolerate light frost and bloom in bright colors like yellow, purple, or white.
Plant impatiens outside after the last spring frost.
Impatiens plants struggle in cold temperatures, so plant them only when the last spring frost has passed. If you want to get a head start, you can start your seeds indoors nine weeks before the last frost and then transplant the seedlings outside.
The general rule of thumb is that most plants freeze when temperatures remain at 28°F for five hours. Of course, there are exceptions to this rule. Seedlings, with their tender new leaves, often give up the ghost when temperatures dip to 32-33°F. Tropical plants have differing low-temperature thresholds.
Each plant has a different threshold when it comes to dealing with the cold. Some plants can survive outside even when temperatures hit freezing. Others need to be brought indoors when temperatures reach the mid-40s. Be sure you know this before you plant.
Light freeze - 29° to 32° Fahrenheit will kill tender plants. Moderate freeze - 25° to 28° Fahrenheit is widely destructive to most vegetation. Severe or hard freeze - 25° Fahrenheit and colder causes heavy damage to most plants.
Zones in Massachusetts range from 5a in the Berkshire mountains to 7a on Cape Cod. Most of western Massachusetts is in zone 5b, while most areas in coastal eastern Mass are now designated as zone 6b, where the average annual extreme minimum winter temperature is between 0 and -5 degrees F.
In many areas of Massachusetts, the last frost date is usually around May 15th. Count back the number of weeks from when each vegetable is to be transplanted into the garden. That will tell you when to start your seeds indoors. Seeds of root crops should be sown directly into the garden.
Perennial flowers to plant in April
Plant hardy perennials, such as daylilies and delphiniums. Later in the month, when the weather settles, set out transplants of: Forget-me-nots (Myosotis spp.) Foxglove (Digitalis spp.)
Spring blooming bulbs can be planted any time as long as the ground isn't frozen. Shrubs and trees can be planted, however, earlier in fall is better as it allows for best root establishment before winter.
It is OK to start planting trees, shrubs, perennials and ground covers in early spring, as long as the soil conditions permit. For instance, there are some shady areas in my garden that still have frost in the ground — avoid working the soil in any areas that are still frozen or too wet.
Flowers that come back up from their roots every year in the springtime are called “perennial” flowers. Some of the best perennial flowers to grow in a garden are peonies, daylilies, coneflowers, and hollyhocks.
Autumn is a great season for annuals, low-maintenance perennials and evergreen shrubs to shine. In fact, some of the most popular flowers, like colorful mums, roses, dahlias, purple pansies and yes, even bright yellow sunflowers, all bloom around September and October.
Plant Annual Flowers in March Gardens
By the end March, gardeners in frost-free regions can begin planting warm-season annuals such as angelonia, wax begonia, and zinnia. Northern gardeners can start setting out cool-season favorites such as pansy, osteospermum, and alyssum.