Gadenin日本語Get the appEverything you do is about avoiding a check
Celosia flowers in response to stress. Cold, drought, root restriction or starvation all tell the plant that its life is about to end, and its answer is to throw a flower head immediately on whatever body it has managed to build. That head then lasts for weeks, looking respectable, while the plant underneath does nothing more all season. This is the single behavior that explains almost every disappointing celosia.
The consequence is that care is largely negative work: keep the plant from ever being short of anything during the first six weeks in the ground. Once it is 12 to 18 in (30 to 45 cm) tall with a strong stem and plenty of leaf, a dry week or a cool spell no longer does permanent damage, and you can relax considerably.
There is no repair for early flowering. Cutting the premature head off gives you side shoots, and those side shoots are better than nothing, but the plant will stay short. Treat this as a reason to get the first month right rather than as something to fix later.
If you have a plant that flowered at six inches tall, cut the head off just above a leaf pair and feed the plant. You will get several smaller heads on side shoots, which is a usable result even though the plant will never reach full height.
Water deeply, and water the soil
Celosia wants soil that stays evenly moist without being soggy, which in practice means a long soak when the top inch (2.5 cm) is dry rather than a splash every day. Push a finger in to check rather than watering on a schedule, because the plant's own appearance is a poor guide until it is already wilting. A wilted young celosia has already taken the check you are trying to avoid.
Water the ground, not the plant. Both the plumed and crested forms hold water in the head like a sponge, and a soaked head in humid weather browns from the inside and can take the top of the stem with it. Aim a can without a rose at the base, or run a soaker hose along the row, and water in the morning so anything that does get wet dries within the hour.
A mulch of 1 to 2 in (2.5 to 5 cm) of compost or fine bark laid once the soil is properly warm is the most useful thing you can do for celosia in a hot summer. It keeps the root zone from swinging between saturated and bone dry, which is exactly the swing that triggers premature flowering. Keep the mulch pulled back an inch from the stem itself.
| Situation | What the plant does | What to do |
|---|---|---|
| Top inch of soil dry, hot weather | Growing well, leaves firm | Soak deeply, roughly twice a week in open ground |
| Wilting in the afternoon, firm by morning | Normal heat response | Nothing. Check again at dawn before adding water |
| Wilting at dawn | Genuinely short of water | Soak immediately and mulch. Expect some growth check |
| Lower leaves yellowing, soil constantly wet | Roots suffocating or rotting | Stop watering, improve drainage, do not feed until it recovers |
| Head browning from the inside after rain | Water trapped in the flower | Cut the head off, and water the base only from now on |
| Container drying out every day | Pot too small for the plant | Move up a pot size now rather than watering twice daily |
Feed lightly and stop when the heads color
Celosia is not a heavy feeder, and overfeeding with nitrogen gives you a tall soft plant with big leaves, a small head and a stem that folds in the first storm. Work an inch (2.5 cm) of compost into the bed before planting, then give a balanced liquid feed at half the label strength every two to three weeks through the growing period. That is enough.
Once the heads are coloring up, switch to a feed lower in nitrogen or stop feeding altogether. Late nitrogen keeps the plant producing soft leaf at the point when you want it hardening its stems, and soft stems are the reason tall plants end up flat on the soil in late summer.
Container plants are the exception and do need more. A pot exhausts its compost in about six weeks, and a celosia that runs out of food in a pot does exactly what a root bound one does: it stops and flowers. Feed potted plants at half strength every week from a month after planting, and use a pot of at least 8 in (20 cm) across for a dwarf type, 12 in (30 cm) for a tall one.
Support the tall kinds before they lean
The tall cutting types carry a lot of weight at the very top of a single stem, and a crested head after rain is heavier than it looks. Once a plant is knocked over its stem kinks permanently and every head on it curves, which for drying and arranging is the difference between a usable stem and a wasted one.
Put the support in when plants are around 12 in (30 cm) tall. Netting stretched horizontally at that height, so the plants grow up through it, is the least work and gives the straightest stems in a block. Individual stakes work for a few plants, but tie loosely with soft string in a figure of eight, because the stems thicken quickly and a tight tie cuts in.
Pushing stakes in later drives them through a root system you have spent two months growing, and the root damage causes the same check that everything else in this guide is trying to prevent. Do it early or use netting.
- Set netting or stakes at 12 in (30 cm) of growth Horizontal netting at that height lets the plants grow through it and holds every stem straight without any tying. Raise it once more if the plants get very tall.
- Tie loosely in a figure of eight Use soft string with a loop around the stake and a loop around the stem. A tie tight enough to hold the stem now will strangle it within a month.
- Strip the lowest leaves at 18 in (45 cm) Remove foliage from the bottom 4 to 6 in (10 to 15 cm) of the stem. It improves airflow at the base and those leaves are where leaf spot starts.
- Pinch the growing tip only on branching types Pinching a plumed or spiked type at 8 in (20 cm) gives more, smaller heads. Never pinch a crested type you want a single large comb from.
- Keep the base clear Pull weeds and keep mulch off the stem itself. Damp material against the stem base is the direct cause of stem rot in humid weather.
Mark on a sketch of the bed which plants leaned and where. It is nearly always the same end of the row, the windward one, and next year that end gets netting first and closer spacing.
Heat is an advantage, not a problem
Celosia comes into its own in the part of summer when petunias go leggy and lobelia gives up. It will keep flowering through weeks in the high eighties and nineties Fahrenheit (30C and above) provided it has water at the root, and full sun for six to eight hours a day is what produces the strongest color and the stiffest stems. A shaded celosia is a floppy, pale, disappointing thing.
The one heat related failure is a plant in a small dark pot in full sun, where the compost hits temperatures that cook the roots and dries out twice a day. Use a light colored, generously sized container and mulch the surface of the compost, and the same plant will thrive in the same spot.
It stops at the other end. Growth slows sharply below 60F (16C) and the first frost kills the plant outright, so late summer heat is worth having rather than dreading. Take advantage of it by feeding and watering properly through the hottest weeks instead of easing off.