February 2021 Culture, Variety Info

Culture Report: Plectranthus Velvet Collection By Chuck Pavlich

A distant relative of the mint family, plectranthus hail mostly from South Africa, where they grow into mighty shrubs. Almost unknown 20 years ago, plectranthus have become an important placeholder in shelf space at the retail level in the last several years. Terra Nova’s plectranthus Velvet collection has greatly improved both the habit and flower size of the species types they originated from. Five distinct varieties are available and offer a much-extended bloom time, in addition to the improved floral and growth habit aspects of the breeding. Two of the varieties, Idol and Starlet, offer excellent “no pinch, no PGR” performance.

CULTIVAR DESCRIPTIONS

Plectranthus ‘Velvet Elvis’ was Terra Nova’s first plectranthus improvement, and it gave the industry the large flowers that earlier breeding lacked. With superbly dark and glossy foliage, it was a star performer and quickly gained popularity showing its blue-purple flowers over a very long time.

‘Velvet Diva’ is an exceptionally heavy-flowering variety with large racemes of lilac-violet that cover the entire plant. Its glossy, mallard-green foliage is the perfect foil for the flowers, making them pop in a flamboyant display.

The likes of plectranthus ‘Velvet Idol’ have never been seen previously. Very large, bright, icy blue flowers on short, dense spikes flood this plant with cool color. ‘Velvet Idol’ has a tight, compact habit that requires no pinching or PGRs.

‘Velvet Starlet’ has the strongest carmine-pink flowers available in this genus. Its naturally compact habit and stunning floral display make this new cultivar “eye candy” for certain. Starlet grows perfectly for either 4- or 6-inch pots.

Plectranthus ‘Velvet Lady’ is a delightful combination of bright, rose-pink flowers in large racemes and healthy pine-green, semi-glossy leaves. This showstopper blooms for a very long time and is easy to grow. It is also quite vigorous, lending itself to larger container combos.

CULTURE NOTES

Always start with certified virus-free stock from a trusted source.

Plectranthus are short-day flowering plants. It is important to keep them vegetative while rooting and growing on. Twelve hours or less of daylight will trigger flowering and stop vegetative growth.

Plectranthus root easily from cuttings, using a 0.1% IBA compound and bottom heat. Soil temperature should be 70 to 75° F until roots show at the edge of the liner cell, which usually occurs at 14 to 21 days. Relatively high humidity is important, but foliage should not be under constant mist. A tented bench works well.

Soilless media should have a good aggregate. Good drainage is very important to plectranthus, as wet growing media can set up conditions conducive to Botrytis, Pythium and Rhizoctonia. Maintaining a constant feed of 150 to 225 ppm of nitrogen is recommended. High levels of nitrogen can cause stretching and result in open, poorly shaped plants. A balanced, slow-release fertilizer can be mixed into the soilless media as a supplement. It is recommended to maintain a pH of 5.5 to 6.5 with an EC of 0.75 to 1.0.

Ambient air temperature should be maintained at 75 to 80° F during the day and 60 to 65° F at night.

For best results, give plectranthus ‘Velvet Elvis’, ‘Velvet Diva’ and ‘Velvet Lady’ one pinch after transplanting to promote branching. Branching occurs soon after pinching or transplanting. Plectranthus ‘Velvet Idol’ and ‘Velvet Starlet’ branch well without pinching or using a PGR.