Costus spectabilis (Fenzl) K.Schum.
Spiked Spiralflag Ginger, Indian Head Ginger
Alpinia spicata, Amomum petiolatum, Costus conicus, Costus cylindricus, Costus micranthus, Costus quartus
Bloom Time: Spring and summer
Costus spicatus is a herbaceous, perennial plant up to 7 feet (2.1 m) tall, that grows from rhizomes. It has tropical-looking foliage with leaves that spiral around the main stem. The leaves are up to 1 foot (30 cm) long and up to 4 inches (10 cm) wide. It produces a short red cone, from which red-orange flowers emerge one at a time. It flowers in spring and summer or year-round in tropical conditions.
USDA hardiness zone 8b to 10b: from 15 °F (−9.4 °C) to 40 °F (+4.4 °C).
How to Grow and Care
Costus fall into the tropical category, so if you do well with philodendrons and other tropical plants, you should be able to grow Costus without too much issue. They aren't terribly picky about their light, but the key to successful growth is lots of water and lots of fertilizer to keep up with their heavy demands. If your plant starts to suffer from brown leaf margins, it most likely is being underwatered or exposed to cold drafts. Try to raise the humidity and increase the water. Costus are susceptible to mealybugs and aphids. Keep a careful eye on your plants and inspect them to catch infestations early and treat them immediately. Severely infected plants should be discarded.
Depending on the species, you'll probably need to repot your Costus annually, at the beginning of the growing season. If you want to keep it a manageable size, use this as an opportunity to divide the rhizome and refresh your potting soil, but keep it in the same size pot. Some of the larger species can grow to 10 feet (3 m) or more, so be aware of the potential size issue… – See more at: How to Grow and Care for Costus
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