• The newer vincas are easier to start from seed than their predecessors. They do take time to flower, however, so start seeds indoors 12 to 16 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 degrees Fahrenheit. Make sure to harden off seedlings for a week to 10 days prior to planting in the garden.

Light

• Annual vinca loves full sun. It will tolerate part shade but may become leggy if there is too much shade.

Soil

• Vincas demand well-draining soil. Add compost or grit to your heavy soil; alternatively, plant vincas in raised beds or containers with a porous, well-draining potting mix.

Water

• Watering too frequently is a common mistake with annual vinca. Water when the top inch of soil feels dry to the touch. A moderate weekly watering is ideal, but do not water at all if your garden is getting regular rainfall. This is a plant that thrives in dry soil.1

Temperature and Humidity

• This plant thrives in hot and humid weather. It will languish a bit if planted too early in the cool spring, and will begin to diminish as the weather cools in fall.

Fertilizer

• Apply compost to the bed, or use a slow-release fertilizer at planting time. Container grown plants need more frequent feedings, as nutrients leech from the soil as water drains.