The Garden Begonia Evolution

Whopper Rose/green leaf

'Big Red Begonia/bronze leaf

Wax begonias (Begonia x semperflorens) are popular summer annuals in flower gardens and containers. Over the last few years new interspecific hybrids have changed how we garden with wax begonias.

Hybrid begonias bloom non-stop for almost six months (mid-May thru October (USDA hardiness zones 6 and 7). Plants stand up to summer heat, humidity, and dry spells, and the foliage stays mostly pest and disease free.


Plants grow vigorously, 18 to 24 inches tall and wide by the late summer/early fall. This means fewer plants to purchase to fill the garden space which will save you money. Space hybrid begonias around 15-18 inches apart depending on which of the three series that you plant.


Hybrids boast larger and showier flowers than the traditional wax begonias. Flower size varies from 2 to 3 inches across. The brightly colored blooms are visited by many kinds of butterflies over the long bloom season. Flowers are self-cleaning and require no deadheading. Plants are compact and well-branched.

Bronze-leaf types grow best in full sun, and green leaf cultivars thrive in partial shade.

Begonias need a well-drained soil with lots of well-rotted compost added. Green leaf types tend to scorch under intense sun.

They perform best with moderate fertility and are not heavy feeders. At spring planting, feed with a slow-release fertilizer such as Osmocote™ 14-14-14 or Nutricote™ 13-13-13. Add 1 to 2 feedings in mid-summer with a water-soluble fertilizer (such as Miracle-Gro®, Schultz®, or Jacks®) southern climates (zones 6-9).

Add 2 to 3 inches of mulch for weed suppression and to conserve soil moisture. Irrigate during extreme dry spells to maintain plant vigor, and flower numbers.

Intersspecific Hybrids Begonia Cultivars:

Big™ series are available in bronze-leaf (full sun) and green leaf (part sun) forms; flower color choices are red, rose and pink.

Whopper™  series come in red and rose colors only and are available in bronze-leaf and green leaf types. Whopper plants tend to grow 20-25% larger than Big.

Megawatt™ series. Current varieties include 'Red Green Leaf', 'Pink Bronze Leaf', 'Rose Green Leaf', 'Red Bronze Leaf' and 'Rose Bronze Leaf'; new color choices will be added in 2018.

'Bluebird' Aster A Top Coice In Mt. Cuba Evaluation Trial

Bluebird aster (Symphyotrichum leave 'Bluebird') is a top selection of U.S. native smooth aster. Bluebird was found in 1988 in a Guilford, Connecticut garden and introduced by Dr. Richard Lighty who at the time was working at Mt. Cuba Center in Greenville, DE in 1994. This tall, vase-shaped wildflower produces large 1 inch wide violet blue flowers on 3-4 feet tall stems. It has attractive, slightly glossy, blue-green foliage that is highly disease- and pest-free.

Bluebird smooth aster thrives in full sun to light shade with a broad tolerance of soil types and moisture levels. Bluebird aster will grow and bloom in part shade, but flower count will be less. In 2016 Bluebird aster was ranked as the #1 aster in an evaluation study at Mt. Cuba Center.

Spring-summer care tip: Prune off old growth from last fall and feed with 10-10-10 or equivalent granular fertilizer. Supplement with water-soluble Miracle-Gro once in mid-summer. Pinch back the young shoots in June for develop a dense plant habit and more flower buds. If left alone, the plant gets too tall and require staking in late summer as flower buds are setting up.

Bluebird aster is a great nectar source for migrating monarch and other late season butterflies.