Each type of plant has specific requirements to thrive and grow in your garden. This begins with the decision of when to plant your flowers. Creating a healthy, beautiful garden requires thought and planning that includes choices of plants, evaluation of sunlight and soil drainage. There's isn't any single cared in stone best time to start planting flowers. Planting too early will strain the plants with exposure to heavy rain or frost. Planting too late will stunt growth.
Ultimately, weather dictates the best time to plant both annuals and perennials. However, plant needs differ. Heavy spring rains can smother a plant with too much moisture causing root rot. Continual days of rain don't allow enough exposure to sun to help a budding plant thrive. Planting before the final frost can drastically harm the new leaves of bedding plants, causing curled leaves and frost burn that permanently damages the plant. It's best to allow the soil to rise to a temperature of 60 degrees before planting tender annuals such as petunias, geraniums and marigolds.
Nurseries grow annuals in a controlled environment inside a greenhouse. As a result, the annual plants that you see and purchase have been nurtured under optimum conditions for growth. These plants have been protected from cold, wind and excessive rain. You're buying the healthiest plant possible and you need to maintain that health for long term blooms. Annuals cannot handle frost at all nor can these bedding plants handle cold temperatures. Annuals should always be planted after the danger of frost completely passes. If a late frost sneaks up on you, cover your annuals with sheets or newspapers to protect the plants.
Perennials grow and thrive quite differently than annuals. These plants can remain in the ground throughout the seasons without much interference from humans. Temperature changes, frost, wind, cold and snow don't really affect a slumbering perennial plant. When the plant decides the time is right, it will form shoots and begin to grow. Hostas are the perfect example of a perennial that pops up on its own terms when the time is right.
Some nurseries grow perennials outdoors for this very reason. Perennials are conditioned to grow under different circumstances than annual plants. Most nurseries grow perennials in a container although bare root perennials with the dirt washed free of roots are also available. Bare root perennials need special care and warmer soil temperatures. Standard potted perennials need a week to acclimate to new weather conditions. Protect the plant from wind and frost for this first week and then transplant it into the ground.
Seeds occupy a whole different arena of plant care. Seeds should be started inside, if possible, in peat pots or small cups filled with potting soil. During the first 7 to 10 days, seeds need moisture and warmth but not direct sun. Starting seeds inside provides a controlled environment to protect these tender plants from harm. It's certainly possible to plant seeds in the ground for both flowers and vegetables. Plant seeds directly into the ground after every danger of frost is past.
Ask for Advice
Always check the labels for the appropriate care for each plant you purchase and transplant. If you have any questions, consult your local garden center for recommendations on the best times to plant any variety of flower in your garden, including vegetables. Your local nursery has the best advice for local climate and planting conditions. Use this resource to save yourself money and time to prevent planting too early and killing your fledgling plants.