Annuals that Thrive in Sun and Heat

    Agave scbra x 'Fernandi Rex' with Calibrachoa 'Coralberry Punch'. Photo by the author, Erica Glasener.Annuals have long been popular in our gardens for summer color in containers and in the garden to help fill the gap when spring perennials finish blooming.  Depending on where you live in the US, there are many varieties to choose from.  Today, gardeners can benefit from the Trial Gardens and plant evaluation programs throughout the country.  Plants (including many annuals) are grown in display beds and rated for things like number of flowers, leaf color, uniformity of habit and flower, resistance to insects and diseases and overall appearance. On a recent visit to Epcot, I was impressed with their Trial Gardens of 100 different varieties of annuals. 

    Below is a list of some of my top choices for Sun. (Stay tuned for a list of my picks of annuals for Shade.)

    • Angelonia has been around but each new selection seems to get better and better.  It takes the heat and humidity and is a nonstop bloomer.  One of my favorite cultivars for 2012 is ‘Serenita,’ a compact and prolific bloomer; it grows 6-10inches high and 4-6 inches wide.  It comes in white, lavender and lavender pink.
    • Calibrachoa ‘ Superbells Coralberry Punch’ is perfect for containers.  Make sure it has a well-drained soil; it hates wet feet.  This sun lover looks like a miniature petunia and grows 8-12 inches high and has both a mounding and trailing habit.
    • Cleome, also known as cat whiskers or needle and thread, is an old fashioned favorite because it is tough and grows in poor soil and full sun.  The drawback is that it can spread and reseed quickly through your garden.  The improved selections (Proven Winners TM) ‘Senorita Blanca’ with white flowers and ‘Rosalita’ with pinky violet flowers have smaller flowers a more compact habit and no stickiness or nasty thorns.  They grow 2 feet to 4 feet tall and are sterile, so reseeding should not be a problem.
    • Salvia coccinea ‘Summer Jewel Red’ is a selection of the native scarlet or Texas sage.  It also received the 2011 Bedding Plant Award for the AAS (All America Selections). It thrives in full sun and has a compact habit, growing up to 20” tall.  It is a must if you want to attract hummingbirds and butterflies.  There are some reports that it will also grow in part shade.  This plant is considered a tender perennial but is commonly grown as an annual too.
    • Zinnia marylandica ‘Double Zahara Strawberry’ is in good company with the other Zahara introductions.  Disease resistance, long season of bloom and drought tolerance make this series award winning.  Plants grow 16 to 20 inches tall.  

    Trial Gardens around the US include:

    • The Trial Gardens at UGA, Athens, GA where they grow annuals, tropicals, vines, perennials and container plantings
    • The University of Tennessee Gardens, Knoxville, TN
    • The Chicago Botanical Garden, Glencoe, IL, evaluates perennials, trees and shrubs
    • Denver Botanic Garden, Denver, Colorado in cooperation with Colorado State University has a plant evaluation program called Plant Select. The purpose is to seek out and identify superior plants from the intermountain region to the high plains
    • The Franklin Park Conservatory, Columbus, Ohio
    • Pennsylvania State University, Landisville, PA (research location).

    What are your favorite annuals? Tell us! We love to hear from you!

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