The Plant: Pentas lanceolata - is the same plant as Pentas carnea - also known as Egyptian Star Cluster Plant. the names are synonymous.
Pentas is the singular - not the plural so the use of the word 'Penta' for the name of this houseplant is incorrect. It is one of a genus of evergreen shrubs and perennials originating from the Middle East and Africa. The shrub has bright green oval leaves and the flower heads are made up of tiny star-like flowers ranging in colour from blue, through lilac and pink-red through to white or purple.
The Pentas can flower at any time of the year, but most commonly in winter. Whilst they are small shrubs in their natural habitat, they have to be grown as houseplants - or under glass in the non tropical areas.
Its needs: Pentas like good light but no t direct sun during the hottest part of the day, and a winter minimum of 10C.
Water regularly throughout the growing season and feed during summer, reduce watering over winter. Mist occasionally to increase humidity. To maintain a neat compact plant pinch out the growing tips in spring. If you want to promote winter-flowering then remove the buds which have formed at the beginning of autumn. The Pentas should be re-potted each spring in a rich organic mix.
Pentas grown as houseplants or under glass will normally need restrictive or formation pruning. This can be carried out at any time of the year - spring probably being best to allow the plant to fully recover and continue growth.
Good for: An attractive winter-flowering houseplant. Easy to maintain.
Seed - if it can be obtained - is a good way to provide additional plants - with a range of colours. Softwood cuttings being the normal method for just the odd plant or two.
Pentas rarely suffer from any fungal disease, though mildew can possibly occur when grown indoors.
As with many houseplants, Pentas can attract greenfly and other aphids, together with red spider mite. Weekly close inspection normally nips the problem in the bud so to speak!
Other Pentas include
Pentas 'Californian Lavender'; Pentas 'Orchid Star'; Pentas 'Tu-Tone' - a bicolor flower od red and pink.