Dahlia

Meet the dahlia, the show-off of the flower bed. A single bloom can be a flat saucer, a ball or a spiky star, in red, orange, yellow, pink, white, deep maroon and every blend, and the plants range from a 30 cm bedding edge to a bush well over a metre tall. It grows from a tuber, a swollen root that stores the plant's energy.

It is a Mexican and Central American plant. Wikipedia describes the genus as bushy, tuberous, herbaceous perennials from Mexico and Central America, found at 1,500 to 3,700 metres in pine-oak woodland, a mountain climate. That is not a description of Dubai. UF/IFAS, writing for Florida, calls dahlias summer-flowering perennials that are challenging to grow successfully there, and tells gardeners to choose a heat-tolerant variety and a spot with light afternoon shade.

So the mood is ambitious. In Dubai a dahlia is a cool-season attempt, not a certainty: plant in the cooler months, give it sun, sheltered ground and steady water, and enjoy what it gives before the heat of May ends the run.

Garden dahlias descend from Mexican species, and Wikipedia says the garden dahlia is usually treated as the cultigen Dahlia variabilis, with an obscure origin, while Kew's WCVP accepts Dahlia pinnata as the name for the species. Thousands of hybrids exist. The RHS says bedding types grow up to 60 cm, most cultivars about 1.2 m, and a few over 2 m. Dahlias are tender: frost kills the foliage, which is not an issue in Dubai, but heat is.

The RHS says dahlias need a warm, sheltered, sunny spot with fertile, moist soil that drains freely, dislike very dry conditions and rot in waterlogged ground, and need extra water in hot, dry weather. It advises mulch, pinching out the growing tip at about 40 cm, staking most types and deadheading weekly. UF/IFAS says dahlias are challenging in Florida, recommends a heat-tolerant variety and light afternoon shade, and says pests and diseases are the norm rather than the exception. In Dubai's dry air, the RHS notes that powdery mildew appears in dry conditions and that red spider mites are a pest, so keep plants well watered and check the undersides of leaves.

We found no Dubai source on planting dates for dahlia, and none from Dubai Municipality. The cool season is the sensible window, with plants in the ground from about October to January so that they grow and flower through the mild months. Plantshop.me lists 'Dahlia Plant - Flowering - Outdoor Plants', and Plantsworld lists a Fito 'Dahlia Decorative Mix' as seed; seeds will not give a flowering plant as soon as a nursery plant or tuber. The ASPCA lists dahlia as toxic to dogs, cats and horses, with mild stomach upset and mild skin irritation.