The top problems red hot pokers have are three: crown rot, thrips, and slugs. Most plants get hit by one of these in their life. Each one has a clear fix. You can stop most issues before they start with good site choice and care.
I lost my first big clump to crown rot five years ago. I planted in heavy clay soil. The rains came hard in November. By spring, the whole crown was soft and brown. The plant never sent up new shoots.
The fix was simple. I built a raised bed with 30% grit mixed into the soil. My new plants in that bed have not rotted in three years. Raised beds solve most kniphofia diseases that come from wet ground.
The plant evolved in fast-draining African mountain soils. Soggy ground triggers rot from fungal germs at the crown. Clemson Extension lists root rot as the top killer of kniphofia in home gardens. Most cases trace back to bad drainage at the planting site.
The next worry is thrips on the flower spikes. These tiny bugs feed on the buds. They leave brown streaks or pitted dots on the flowers. Bad cases can ruin a full bloom display. Check your spikes once a week from June through August.
I caught thrips on my Pyromania plants two summers back. The first sign was silver streaks on the orange florets. I sprayed the spikes with a strong jet of water at dusk. Three sprays in one week knocked the bugs back. The next bloom came in clean.
Crown Rot
- Cause: Soggy soil at the base of the plant from heavy clay, poor drainage, or low spots that hold water in winter.
- Sign: Soft, brown crown in spring with no new growth and a sour smell at the base of the rotted clump.
- Fix: Move your plant to a raised bed with 30% grit in the mix, or build a mound at least 6 inches (15 cm) high.
Thrips on Spikes
- Cause: Tiny bugs that fly in from other plants and feed on the buds and open florets in hot dry weather.
- Sign: Silver streaks, brown spots, or pitted dots on the flower color which spoils the spike look.
- Fix: Spray spikes with a strong water jet at dusk three times a week, or use insecticidal soap if bad.
Slugs and Snails
- Cause: Cool damp weather in spring brings out slugs and snails that chew the new leaves at ground level.
- Sign: Ragged holes in young leaves and slime trails on the soil near the base of your plant.
- Fix: Hand-pick at dusk with a flashlight, or set out beer traps and iron phosphate bait around the crown.
Slugs are the third top red hot poker pests, mostly in cool wet climates. They eat the young leaves in spring. Hand-pick them at dusk. Set beer traps or use iron phosphate bait. These three tricks knock back slug damage in one week.
Poor flowering is the fourth common gripe with kniphofia. The cause is almost always a tight, old clump. After five years, the center dies out. The plant makes lots of leaves but few flower spikes. Your old plant looks tired all summer.
Good kniphofia troubleshooting starts with a yearly check. Dig and split clumps every five years in early spring. Add fresh compost back to the hole. Plant the best three or four pieces. Your bloom count will triple in the next season.
Stay on top of these four issues and your plants will thrive. Check for thrips each week. Pick slugs at dusk. Split tight clumps on time. Keep the soil sharp and dry. Your kniphofia will give you tall, bright spikes for many years.
Read the full article: Kniphofia Plant Care: Complete Guide
