Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
I’ve always wanted to try red hot pokers in my garden but their orange and gold blossoms just don’t go with my other pastel flowers. Then I had a chance to see them growing in person instead of in a catalog and realized that even if their color was a good fit, the plants are much too large for my tiny garden.
What are Red Hot Pokers?
Red Hot Pokers (Kniphofia uvaria), which are also called Torch Lilies, are native to South Africa. Here in the US, they are hardy in zones 6 -9. You can grow them as far north as zone 5 with protection during the winter.
Red hot poker plants grow from rhizomes which spread easily. It has naturalized in the parts of the world where it has been introduced and is considered invasive in southern Australia and southern California.
The larger cultivars grow 4 – 5 feet tall and up to 3 feet wide, while dwarf varieties grow 1 – 2 tall and 1 foot wide. Unlike their cousins the aloes, red hot poker leaves are not thick and succulent. They are similar in shape though, sword-like with sharp pointed ends. The edges are also sharp so deer and rabbits stay away.
The leaves grow directly out of the rhizomes, similar to iris. They are evergreen in warm climates and deciduous (lose their leaves in the fall) in colder areas.
The flowers are eye-catching. Like iris, they grow on a stem that arises from the rhizome. They are tubular and grow in clusters that are shaped like a bottlebrush. The flowers are red or orange but turn yellow or gold as they age, giving them the appearance of a torch, from which they got their other name, Torch Lily.
Bloom time is late spring to early summer. The flowers will last up to 18 days on the plants. Butterflies, bees and hummingbirds find them irresistible. Remove spent flowers to encourage new ones to grow. If you do not remove them, they will start to form seed and the plant will not produce any new flowers.
How to Grow Red Hot Pokers
Because of their size, red hot pokers should be planted 18 – 24 inches apart. Dwarf varieties can be planted closer together or in a pot.
Red hot pokers enjoy full sun but will tolerate some shade. In the warmer parts of its range, a little afternoon shade is welcome. The plants will grow in almost any soil as long as it is well-drained. They are susceptible to crown rot in wet soils. The pH should be neutral to slightly acidic.
The first year in your garden, keep your red hot pokers evenly moist as they become established. After that, they can withstand short periods of drought. Provide them with 1 inch of water each week, allowing the soil to dry slightly between waterings.
How to Protect Red Hot Pokers in the Winter
Depending on where you live, different strategies are employed to make sure your plants survive the winter. In the warmer parts of its range, where the foliage is evergreen, bind the leaves together to protect the crown from becoming too wet and rotting.
In the zones where the plants are deciduous (lose their leaves in the fall), cover your plants with a thick layer of leaves to protect them through the cold and wet of winter.
In the farthest north, zones 5 and 6, employ both strategies. Cover the crowns with a thick layer of leaves, then tie the plants’ leaves together to keep the leaf cover in place and provide extra protection.
How to Divide Red Hot Pokers
Like most perennials, your clump of red hot pokers will enlarge every year. You will be tempted to divide it, but it’s not a good idea. Dividing it will injure the rhizomes. The best way to prevent your red hot pokers from becoming too large and overcrowded is to remove the offsets and replant them.
Offsets are baby plants that grow around the exterior of the rhizomes. In the spring, carefully dig around the baby plants and check to see if they have roots. You only want to remove the ones that have roots. Use a clean, sharp knife to cut the offset from the main rhizome.
Plant your offsets 18 – 24 inches apart in a sunny location. Keep them evenly moist during their first year as they become established in their new homes. After the first year, you can go back to watering them 1 inch per week.
How to Grow Red Hot Pokers From Seed
Red hot pokers can be grown from seed. The easiest way is to allow the flowers to die and go to seed. The seed will drop to the ground and germinate the following spring. They need a period of cold weather before they germinate.
If you would like to start seeds indoors, you will need to cold stratify them. 10 – 12 weeks before your last frost, wrap the seeds in a moistened paper towel. Then place the paper towel inside of a plastic bag to keep it moist. Place the bag in your refrigerator for 4 weeks.
After 4 weeks, remove the seeds from the paper towel and surface sow them in peat pots or biodegradable containers. Barely cover the seeds with soil. Place your pots on a heat mat that will keep them at a constant 70°F. Then prepare to be patient. It could take up to 3 months for the seeds to germinate.
Once the seedlings have reached 2 inches in height, they can be planted outdoors in your garden. Plant the entire peat pot so as not to disturb the fragile new rhizome. Space your seedlings 18 – 24 inches apart. They will flower during their second year of growth.
© 2021 Caren White