Gadenin日本語Get the appThree things have to happen, in order
A cymbidium flower spike is the end of a sequence that runs across most of a year, and a break anywhere in the chain means no flowers. First, a new growth must mature into a fat, hard pseudobulb over the summer, which takes strong light and generous water and feeding. Second, that mature bulb must be exposed to a run of cold nights in autumn. Third, the developing spike must be kept cool and left alone through winter while the buds swell.
Most non-flowering plants fail at the first or second stage. A plant grown in indoor light makes narrow, soft pseudobulbs that have no reserves to spend on a spike, and a plant brought indoors at the first cool evening never gets the temperature signal. Neither problem has anything to do with fertilizer, and neither is fixed by moving the plant to a brighter spot in mid winter.
There is a simple test for the first stage. Squeeze a pseudobulb from last summer between finger and thumb. A flowering-size bulb is hard, about the size of a hen's egg or larger, and does not give at all. If your bulbs are thin, soft or barely wider than the leaf bases, the plant is not yet strong enough to bloom and the answer is a full season outdoors, not a change of feed.
| What you see | Likely cause | What to change |
|---|---|---|
| Big plant, dark floppy leaves, no spikes | Not enough light all summer | Move it outside for the whole growing season |
| Good stiff yellow-green leaves, no spikes | No autumn cold, brought indoors too early | Leave it out until frost is actually forecast |
| Thin pseudobulbs, plenty of new leaves | Too much nitrogen, or too little light | Cut nitrogen after midsummer, raise the light |
| Spikes appear, then buds yellow and drop | Warm dry air, or the plant was moved | Keep it at 50F to 60F (10C to 15C) and still |
| Flowered heavily last year, nothing this year | Too few new growths to carry a spike | Feed and water harder in summer, do not divide small |
| Repotted last spring, no flowers that winter | Normal check after root disturbance | Wait a season, repot less often |
Spike or new growth: how to tell them apart
In late summer and autumn, pointed shoots appear at the base of the pseudobulbs, and every cymbidium grower has to learn to read them. Both a flower spike and a new vegetative growth start as a green point pushing out of the same area, and for the first week or two they look similar. The difference is in the cross section, and you can feel it in a second.
Roll the base of the shoot gently between finger and thumb. A flower spike is round, almost cylindrical, and feels like a fat pencil. A new growth is flattened, like a folded fan, because it is a stack of leaves pressed together, and you can feel the two flat faces and the sharp edges. That single test is more reliable than any description of color or shape.
There are secondary clues. Spikes emerge tight against the side of a mature pseudobulb, angle outwards and upwards, and are usually darker and more sharply pointed, often with a slight silvery bloom on the sheath. New growths appear at the outer edge of the plant where the rhizome is heading, sit lower and more upright, and soon show a rounded leaf tip splitting away from the point. Spikes also grow noticeably faster, gaining an inch (2.5 cm) or more a week in autumn, while a new growth is slower and steadier.
| Feature | Flower spike | New vegetative growth |
|---|---|---|
| Cross section when rolled | Round, like a pencil | Flattened, two clear faces |
| Where it comes from | Hard against a mature pseudobulb | At the leading edge of the rhizome |
| Angle | Leans out away from the plant | Stands upright, close and parallel |
| Tip | Sharp, hard, stays pointed | Soon splits into a rounded leaf tip |
| Speed | An inch (2.5 cm) or more a week | Slow and even |
| Season it appears | Late summer into autumn | Mainly spring and early summer |
Staking, and what to do while the spike is growing
Cymbidium spikes are heavy and grow towards the light, so a spike left unsupported curves and then leans until the weight of the buds pulls it over. Stake early, while the spike is still short and flexible. Once it has hardened into a bend you cannot straighten it without snapping it.
- Put a stake in as soon as the spike is six inches (15 cm) tall Push a bamboo cane into the mix beside the spike, angled so it misses the pseudobulbs and the thick roots. Going in early avoids spearing roots later when the pot is full of spike and buds.
- Tie loosely, low down first Use a soft tie or a clip and fasten the spike to the cane just above the first node, leaving room for it to thicken. A tight tie cuts into the tissue as the spike swells and kills everything above it.
- Add a tie every few inches as it extends Follow the spike up with a new tie every three or four inches (8 to 10 cm) of growth, keeping it straight. Stop tying about six inches (15 cm) below the first bud so the flowers can arch naturally.
- Turn the pot a quarter every week until buds swell Even turning keeps the spike upright rather than bending towards one window. Stop turning the moment the buds start to swell, because from then on the flowers set their orientation and further movement twists them.
- Freeze the plant in place once buds are fat Choose the final position before the buds color and leave the plant there. Moving a plant with swelling buds, especially into a warmer or drier room, is the most reliable way to cause bud blast.
If a spike snaps below the buds it will not repair. Cut it cleanly at the base with a sterile blade, put the plant back into its normal routine, and treat the loss as a staking lesson rather than a plant problem.
Bud blast and how long the flowers should last
From spike initiation in autumn to the first open flower is roughly four to five months, so a spike that appears as the nights turn cold opens in the depths of winter or in early spring. Once open, cymbidium flowers are extraordinarily long lasting: eight to ten weeks on a plant held at 50F to 60F (10C to 15C), against three or four weeks in a heated room. Cool is not merely tolerated here, it is what you are paying for.
Bud blast means buds that yellow at the stalk and drop before opening, usually from the bottom of the spike upwards. The causes are warm dry air, a sudden temperature change, letting the pot go bone dry while the spike is filling, and ethylene from ripening fruit or an unflued gas heater. It is almost always an environment problem rather than a pest or disease, and it stops as soon as the environment is corrected, though the lost buds do not come back.
Keep water off the flowers. Cymbidium petals mark with brown spots wherever a droplet sits and then a spore of botrytis lands, especially in a still, damp, cool room. Water into the mix, keep air moving gently, and do not mist a plant in flower.
After the flowers, and what to write down
When the last flower has gone over, cut the spike off close to its base with a sterile blade. It will not branch or flower again, and left in place it draws on the plant and rots back into the pseudobulb. This is also the moment when repotting and dividing is least disruptive, if the plant needs it.
Feed and water resume in full as the new growths start. A plant that has just carried a heavy spike is running on empty, and the growths made in the season after flowering are the ones that must fatten up to bloom the year after, so the recovery period is not a rest period.
Each year, note four things: the date the plant went outside, the date it came in, the number of spikes and which pseudobulb each came from, and the date the first flower opened. After two seasons that record answers most questions on its own. If spikes are set every year but flowers are short lived, the winter room is too warm. If spikes never appear, compare the autumn you left the plant out longest with the ones you did not, and the pattern will be obvious.