Plectrantus ‘Velvet Elvis’ at Longwood Gardens in Kennett Square, PA

Lavender Spur Flower (Plectranthus Mona Lavender™) is a fast growing flowering annuial that is full of lavender blue flowers from late summer to autumn frost (USDA hardiness zones 9-11). Flowers can usually cope with light frosts of 25 – 30° F in early autumn.  Plants grow 2 to 2.5 feet tall and wide forming a round dense plant.

Lavender Spur Flower is best sited in light shade or partial day sunlight, preferably in the morning. In full sun this flowering annual tend to grow more compact and the foliage becomes darker green with a more intense purple hue on the underside. Plant in fairly well-drained soil enriched with humus and water regularly. To encourage compactness and better branching, pinch plants every 2 weeks from planting time to mid-summer. Feed plants every 2-3 weeks with water soluble fertilizers such as Miracle-Gro™ or  Nature’s Source™.

Two cultivars are available in U.S. garden centers:

Mona Lavender™ is the current best selling cultivar withlavender purple flowers and dark green foliage with deep purple underside and stems.

‘Velvet Elvis’ is a new introduction touted to produce larger and deeper lavender blue flower trusses than Mona Lavender. Foliage is deep green and deep purple beneath; plant habit is more compact.

Lavender Spur Flower are best planted enmasse in a front garden border or plant in containers by itself or with other annuals and perennials. Flower spikes attract butterflies and hummingbirds and plants are generally deer resistant. 

Lavender Spur Flower belongs in the same plant genus (Plectranthus) as Swedish Ivy (P. australis). Some may grow it as a houseplant but it will need very bright light to keep blooming indoors.

Suggestion from a blog reader: grow it outside in a hanging basket and overwinter the plant in a greenhouse or sun room.