King Tut Grass (Cyperus) Yellowing in Hot Winnipeg Summer: Fertilizer and Water Fix

Perry in Winnipeg (Zone 3b) has King Tut grass (Cyperus papyrus 'King Tut') in a large ceramic pot, full sun, hot dry summer. Well-watered but suddenly yellowing — all the fine grassy tops, not just lower leaves.

Not Overwatering — This Plant Loves Wet Feet

King Tut grows in pond margins. Yellowing here is not from too much water.

Likely Cause: Hunger

Fast-growing, heavy feeder. In a pot, nutrients leach fast. If you haven't fertilized recently, it's starving.

Two-Step Fix

1. Water even more: Morning and evening soak for a few days. Fully hydrate the root ball.
2. Fertilize: Synthetic liquid fertilizer (e.g., 20-20-20) weekly at half strength, OR controlled-release granules scratched in. Never fertilize a dry plant — water first, then feed.

Check Sun Exposure

Has anything changed? Tree removal, new structure? King Tut needs full sun. If shade increased, that could contribute.

Note: Synthetic fertilizer is fine for annuals like this. Organic is great for perennials/veggies, but annuals in pots need immediate, reliable nutrition.

Within 1–2 weeks, new growth should be deep green.