The arrival of spring signals the start of the gardening season, a time when the ground thaws and the urge to fill beds and containers with color becomes strong. Spring planting requires a careful transition from protected environments to the fluctuating outdoor conditions. Understanding the proper timing and selecting the right plant types ensures a garden that will flourish from early summer until the first hard frost. This guide details the timing and specific flowers to plant once winter has passed.
Understanding Spring Planting Timing
The decision of when to plant is governed less by the calendar date and more by local climate conditions, primarily the last expected spring frost. This date is an average estimate based on historical weather data, often referenced using the USDA Hardiness Zone system. Gardeners must monitor local forecasts, as this guideline is not an absolute guarantee against unexpected dips in temperature.
Beyond air temperature, soil warmth is a determining factor for plant success. Cold soil inhibits seed germination and shocks the roots of young transplants, leading to stunted growth. Many warmth-loving flowers require the soil temperature to be consistently above 60 degrees Fahrenheit before they can thrive. Using a simple soil thermometer provides a more accurate picture than relying only on air temperature.
For flowers started indoors or purchased as young plants, a process called “hardening off” is required before they are permanently set outside. This two-week gradual acclimation exposes tender seedlings to increasing amounts of sunlight, wind, and cooler temperatures. Initially, plants are placed in a sheltered, shaded spot for just a few hours, and this time is extended daily until they can tolerate spending a full 24 hours outdoors. This process causes the plant’s cell walls to thicken, changing the soft, succulent growth to firmer tissue better equipped to handle the elements.
Essential Spring-Planted Annuals
Annual flowers complete their entire life cycle within a single growing season, providing continuous color until the first fall frost. These plants are typically set out once the danger of freezing temperatures has passed for an immediate and long-lasting display. Selecting the right annuals depends primarily on the amount of direct sunlight the planting area receives each day.
For areas that receive six or more hours of direct sun, several annuals offer vibrant, heat-tolerant blooms. Marigolds and Zinnias are classic choices known for their daisy-like flowers and ability to withstand hot summer conditions; Zinnias benefit from deadheading to encourage new blooms. Other sun-loving options include Petunias, which trail well in containers, and Angelonia, which produces upright spikes that add vertical interest. Portulaca, or Moss Rose, is highly drought-tolerant due to its succulent foliage.
In shadier locations that receive less than four hours of direct sun, Impatiens and Begonias are reliable choices for brightening dim spaces. Traditional bedding Impatiens produce a dense carpet of flowers in a wide array of colors from late spring until fall. Begonias, including the Wax Begonia and the larger Dragon Wing variety, offer both colorful foliage and consistent blooms. Coleus is another valued shade annual, grown primarily for its velvety leaves that display dramatic patterns of color.
Perennials and Summer-Blooming Bulbs
Perennial flowers return year after year, establishing a permanent structure in the garden. In spring, these are typically planted from nursery containers or purchased as dormant bare roots. Planting container perennials like Hostas, Coneflowers, and Daylilies allows them to establish a strong root system during the temperate spring. Hostas thrive in shade, while Coneflowers and Daylilies prefer full to partial sun and provide reliable mid-summer color.
When planting bare root perennials, such as Peony or Daylily, soak the roots briefly before planting to rehydrate them. The root mass, or crown, should be positioned in the planting hole so that it sits at or just slightly below the soil surface to prevent rotting. Although growth may be limited in the first year as they focus energy on root development, these plants provide increasingly robust displays in subsequent seasons.
Spring is the time to plant tender bulbs, corms, and tubers, which cannot survive freezing temperatures and are stored indoors during winter in colder regions. These summer-blooming varieties, including Dahlias, Gladiolus, and Cannas, are planted after the last frost date when the soil has warmed sufficiently, ideally reaching 60 degrees Fahrenheit. Gladiolus corms are planted about four inches deep and six inches apart; staggering planting times provides flowers throughout the summer. Cannas, which grow from rhizomes, require a deeper placement of about six inches and wider spacing to accommodate their large foliage.