Kniphofia's architectural flower spikes in fiery shades of red, orange and yellow add an exotic look to summer borders, prairie planting schemes and tropical gardens. These showy perennials are easy to care for, and their nectar-rich blooms are attractive to pollinators.
Even at the height of summer, few perennials make quite such a statement as a kniphofia. Also known as the red hot poker or torch lily, this distinctive plant produces tall flower spikes that rise like flaming torches above its strap-like foliage, adding dramatic colour and structure to sunny borders. Most kniphofias are at their peak in July and August, though some varieties flower earlier, and many keep blooming into early autumn.
Despite their tropical look, kniphofias are hardy in the UK, and they're generally unfussy, long-lived perennials that need little attention once established. Our range of kniphofia plants includes smaller cultivars, which are ideal for growing in pots, as well as taller varieties.
Where to plant kniphofia
Kniphofia is a sun-loving plant that hails from the eastern part of South Africa. When grown in the UK, it likes to bask in plenty of sun, though some varieties will cope with partial shade. Kniphofia is fairly unfussy when it comes to soil type, as long as it's moist and well-drained. It will suffer in very wet winter soil, but may also struggle if the soil is very free draining. In both cases, mixing organic matter into the soil before planting can help improve the conditions.
Most kniphofias grow to between half a metre and a metre in height when in flower, making them an ideal mid-border perennial. There are shorter and taller varieties, with some getting to over two metres, so make sure you choose one that suits your planting site.
With its vibrant colours and exotic style, kniphofia naturally pairs with achillia, rudbeckia and other warm-toned perennials in a "hot border". They also offer a wonderful textural contrast to soft, feathery grasses. For dramatic contrast, plant it alongside its fellow South African native, blue agapanthus, or, in mild, sheltered spaces, use it as a pop of colour in a tropical-style garden.
You can grow kniphofias in pots, but choose a shorter variety, such as Kniphofia 'Poco Citron' or Kniphofia 'Poco Sunset'.
When to plant kniphofia
Spring is the ideal time to plant red hot pokers, as it gives them the summer and autumn months to become established. You can plant them in summer and early autumn, but you may need to water them more frequently to help the plants settle in.
How to plant kniphofia
If you have very light, sandy soil, dig some organic matter, such as compost or well-rotted manure, into the soil before planting to improve the fertility and help it retain moisture. You can add compost and grit to clay soil to help with drainage, but if your soil is very heavy and tends to get waterlogged in winter, you may be better off growing kniphofia in pots or a raised bed.
Dig a hole deep enough to hold the plant in its pot and twice as wide. Remove your kniphofia plant and gently tease out a couple of the thick roots. Place your plant in the hole and backfill the soil so it's at the same level as in the pot. Firm the soil around your red hot poker and water it well.
When planting red hot pokers in pots, choose a large container with good drainage and fill it half full with peat-free compost with added John Innes. Plant your kniphofia so the compost is at the same level as in its growing pot, a centimetre or two below the rim of the container.
How to care for kniphofia
Kniphofia are fairly low maintenance and shouldn't need feeding or regular watering once established, unless the ground gets very dry. New plants will need watering occasionally during their first year to help them establish. On sandy soils, you may want to add a general purpose fertiliser in spring.
Plants in containers will need more regular watering, though be sure to let the compost dry out a bit in between. If you planted your kniphofia in spring, the compost should contain enough nutrients for the first couple of months, after which you can apply a liquid feed every two or three weeks. For older plants, add a slow release fertiliser in spring and repot with fresh compost every few years.
Deadhead kniphofia flowers by cutting the stalks at the base once the flowers fade. Leave the foliage in place, as this helps protect the plant over winter. In spring, you can cut the dead foliage back to the base. If there is any green foliage left, gently pull this away rather than cutting it.
Kniphofias are hardy across most of the UK, but they can struggle with the combination of wet soil and cold weather, which is why it's important to plant them in well-drained soil. If you're growing a less hardy cultivar or your winters are particularly cold, then you can protect plants with straw or biodegradable fleece. Move plants in pots to a sheltered area, such as in front of a south-facing wall, or keep them in an unheated greenhouse over winter. Wrap containers with hessian or bubble wrap to protect roots from frost.
Propagating red hot pokers
The easiest way to propagate kniphofia is to divide mature plants in spring. Use a garden fork to lift the entire clump, then cut it into sections with a sharp shade or knife. Make sure you have at least three strong shoots in each new section. Replant the divisions immediately, either in the ground or in pots. You may not get as many flowers in the first summer, but the plants will recover for the following year.
You can also grow kniphofia from seed, although the new plants won't be exactly the same as the parent. If you have different varieties of kniphofia in your garden, you may end up with some interesting variations! Either plant ripe seeds immediately or keep them in the refrigerator until spring. If you grow plants from seed, you'll need to be patient, as they may take two or three years to flower.
Common problems
Wet winters are the main challenge when growing kniphofia, and wet soil can also lead to fungal diseases such as Phytophthora root rot and Fusarium wilt. Dig up and destroy affected plants and avoid replanting in the same area.
Slugs and snails may munch on new shoots in spring. As the new shoots come up, clear away dead foliage from the previous year and remove any gastropods that have hidden away.
Large aphid infestations can cause the flowers to become distorted and stunt the plant's growth. While a few aphids are unlikely to be harmful, keep an eye on plants and if they're becoming a problem, squash them or use a jet of water to remove them from your plants.
Our favourite varieties of kniphofia
Kniphofia 'Lemon Popsicle' is a mid-height variety with vibrant yellow flowers. It has a long flowering period, from June to September, and is hardier than most red hot pokers, making it a good choice for colder parts of the country.
Kniphofia 'Poco Sunset' has bright orange-red flowers that gradually fade to tangerine, adding a warm glow to beds and pots. This compact variety is ideal for patio or balcony gardens and smaller borders.
Kniphofia rufa 'Rasta' is an unusual variety with flower spikes that gradate from coral red at the tip down to lime yellow. It's a taller kniphofia that can grow to over a metre.
FAQ
When do you cut back red hot pokers?
Remove kniphofia flower spikes once the flowers fade by cutting the stems at the base. Leave the foliage on over winter, then cut back the dead leaves in early or mid spring, once the worst of the cold weather has passed.
When do red hot pokers flower?
Kniphofias or red hot pokers flower in summer in the UK, with the display often extending into early autumn. Most plants are at their best in July and August. There are a few later flowering varieties, such as Kniphofia rufa 'Rasta', which flowers in August and September and Kniphofia rooperi, which doesn't begin flowering until September.
Are kniphofia perennials?
Kniphofias are flowering perennial plants. Most are herbaceous perennials that die back over winter and return the following spring, but there are also some evergreen varieties that keep their leaves throughout the year.
Can you grow kniphofia in pots?
You can grow smaller varieties of kniphofia in pots, and this is the best option for growing red hot pokers if you have very heavy or wet soil. The "Poco" range, which includes cultivars like Kniphofia 'Poco Red' and Kniphofia 'Poco Citron' is an excellent choice for containers. Make sure your pot has drainage holes and move it to a sheltered place in winter, so the compost doesn't become waterlogged.
