Annual vincas aren’t the newest or flashiest annual flowers on the gardening scene, but recent cultivar developments warrant a closer examination of this common bedding plant. Horticulturists have been hard at work cultivating new colors in plants with showy flowers that are easy to start from seed. In a plant that was already reliably drought-tolerant and pest-free, what more could you ask?
Origins of the Name
Also known as the Madagascar periwinkle, annual vinca plants are of the genus Cartharanthus, a member of the Apocynaceae family. This is a case where paying attention to the Latin name is helpful: You must distinguish the annual vinca flower from the perennial vinca minor vine, which forms a dense mat and can be invasive.
The newer vincas are easier to start from seed than their predecessors. They do take time to flower, however, so start seeds indoors at least 10 weeks before your average last frost. Cover the seeds enough to ensure darkness, and use supplemental heat if necessary to provide an ideal germination temperature of 75 F.
Don’t rush to put out vinca plants in the spring. Plants set out too early in cold, wet soil will deliver a sickly performance; after all, these are hot weather annuals. A safe bet is to plant your vincas around the same time you set out your tomato transplants: when evening temperatures average 60 F. Full sun is best, although some afternoon shade is fine.
Fertilize vincas every two weeks with a balanced flower fertilizer to help these prolific performers keep up the blooming momentum. Vincas are free-flowering and self-cleaning, and no deadheading is necessary.
Vinca is drought tolerant, but if you notice the leaves start to curl, it’s time for a drink. Water at the base of the plant, rather than overhead. This helps prevent the two diseases that primarily affect vinca plants, which are branch blight and root rot.
Take advantage of the fast growth habit of vincas. Buy a six-pack of vinca plants as a filler for any blank sunny spot in the garden border where your perennials haven’t matured yet. Trailing annual vincas like the "Cora Cascade" cultivars don't have a big footprint in the soil, but will spill onto pathways and peek through leggy shrubs to add a burst of color.
Bring out the contrasting eye of the vinca flower by pairing them with a flower that matches the flower’s eye. For example, you can plant white vincas with a burgundy eye alongside burgundy zinnias, or pair peach vincas with a red eye with dramatic wine-hued celosia plants.
The low-care nature of vinca plants helps them succeed in window boxes and other garden containers. Pair them with other heat and sun lovers like million bells, moss rose, lantanas, or penta flowers. These flowers will grow more prolifically as temperatures rise, keeping your sultry summer days full of color until fall.
The foliage of vinca plants is dark green and leathery looking. Depending on the variety, the plants are 8 to 18 inches tall and spread from 1 to 2 feet. Vinca plants bear single blooms with five petals that frequently touch or overlap from early summer until the first frost. Many varieties feature a contrasting eye. If you haven’t included vincas in your garden for a while, you should check out the expanded color palette that now includes blooms in every shade of the pink, rose, and lilac spectrum. Peach and white flowers are also available. No matter your preference, all are attractive to butterflies and rabbit resistant:
- Cooler series: A good choice for gardeners with cool summers.
- Heatwave series: Plants have a very compact growth habit.
- Mediterranean series: Plants trail to 2 feet; use in containers and hanging baskets.
- Pacifica series: An early bloomer.
- Soiree Double White: A novelty in the vinca world, this variety produces double flowers for a full, lush look.
- Stardust series: Flowers feature a white starburst in the center. Look for the All-America Selections award-winning "Stardust Orchid."