Gadenin日本語Get the appThe cycle, not the calendar
Oxalis does not fit a seasonal schedule the way a hardy border perennial does. What it has is a cycle: restart, build, flower, decline, rest, and then restart again. That cycle usually takes somewhere between eight and fourteen months in total, so it drifts steadily relative to the calendar, and two pots of the same plant started three months apart will be in different phases all year. Trying to manage it by month leads to feeding a dormant pot and drying out one in full growth.
The useful skill is recognizing which phase a pot is in from what it looks like, because each phase has one thing that matters and several things that are actively harmful. The table below is the whole schedule in one place. The phase lengths are typical rather than fixed, and they shift with temperature: a plant kept warm runs faster and rests less deeply than one kept cool.
One consequence worth planning for is that you can choose when the flowering happens. Because you control the restart date, a rest taken deliberately at the end of summer gives you a pot coming into flower during the darkest months, which is when a mound of purple leaves and pale flowers on an indoor windowsill is worth the most.
| Phase | What you see | The one thing to do | What to avoid |
|---|---|---|---|
| Restart | Bare compost, firm bulbs, no growth for 2 to 4 weeks | One thorough watering, then warmth and bright light | Watering again before shoots appear |
| Build | Shoots up, leaves unrolling, pot filling over 6 to 8 weeks | Water when the top inch (2.5 cm) is dry, turn weekly | Feeding heavily, or low light that stretches the stalks |
| Flowering | Stalks above the leaves, flushes of 2 to 4 weeks | Half-strength high-potash feed every 3 weeks, deadhead | Moving the pot, repotting, or letting it dry erratically |
| Decline | Yellowing from the oldest leaves, stalks going limp | Stop feeding and taper the water over 2 to 3 weeks | Cutting off green foliage, or trying to revive it with water |
| Rest | Bare pot, dormant bulbs, 4 to 8 weeks | Keep dry at 50 to 60F (10 to 16C), label with the date | Any watering at all, and forgetting it for a year |
Restart to first leaves
The restart is the point of decision in the whole cycle, and it takes about a minute. Bring the rested pot out of its cool dark corner, put it somewhere bright at 60 to 70F (15 to 21C), water it thoroughly until it runs from the base, let it drain, and then leave it entirely alone. Nothing you can do speeds up what happens next, and the only way to interfere with it is to water again.
Every second cycle, do this restart with fresh compost. Tip the pot out, break the bulb cluster apart, discard anything soft or hollow, and replant the firm bulbs an inch (2.5 cm) deep and an inch apart in a mix cut by a third with grit. You will nearly always have more bulbs than the pot needs by this point, which is the moment to thin, to pot up a second container, or to give some away. A pot allowed to keep multiplying for several cycles without thinning ends up producing plenty of leaves and no flowers.
Shoots appear in two to four weeks, later if the room is below 60F (15C). They come up as tight pale or pink spears that unroll into folded leaflets over a few days. Start regular watering once the first leaves are open, and hold off feeding for another two or three weeks until the pot is filling out. If nothing has come up after six weeks, tip it out and check: firm bulbs mean the rest is not finished, so dry it off and try again in a month.
Build and flowering: the long middle of the cycle
From the first leaves to the last flower is the great majority of the cycle, typically five to nine months, and it is undemanding. The routine below is the whole of it.
- Water on the top inch, not on a schedule Push a finger an inch (2.5 cm) into the compost and water thoroughly if it is dry there. In a warm bright room that is roughly every four to seven days; outdoors in summer heat it can be every other day. Empty the saucer within half an hour.
- Feed at half strength, and change what you feed Balanced liquid feed at half strength every three to four weeks while the plant is building leaf, then switch to a high-potash feed at half strength once flower stalks appear. Full-strength general feed gives large soft leaves and few flowers.
- Turn the pot a quarter turn every week Both the leaves and the flower stalks lean toward light strongly. A weekly turn, easiest done as you water, keeps the mound even and stops the display throwing itself at the window.
- Groom weekly Pull spent flower stalks and yellowed leaves out at the base with a light tug. It takes a minute, keeps damp dead tissue out of the crowded leaf mound, and reduces both rust and mildew.
- Move it outdoors once nights are above 50F (10C) A summer outdoors in morning sun with afternoon shade produces a far better colored, more compact plant than any windowsill. Harden it off over a week, and check it for aphids for the first fortnight after the move.
- Bring it back in before the first frost Most ornamental oxalis is damaged below about 40F (5C) and killed by a freeze at the bulb. Check the leaves and the compost surface for pests before it rejoins the indoor plants.
Decline and rest: doing less, deliberately
The end of the cycle announces itself. Leaves yellow from the oldest outward, the stalks lose their stiffness, and over two or three weeks the pot empties itself. This is not something to fix, and the correct response is a sequence of things to stop. Stop feeding at the first yellow leaf. Halve the watering and lengthen the intervals. Stop watering completely once most of the foliage has gone over.
Let the foliage die back fully before clearing it. Those dying leaves are moving their reserves into the bulbs, which is what pays for the next cycle's flowers, and cutting them off green while a pot looks untidy is the single most common reason a restart comes back thinner than the season before. When the stalks are yellow or brown and pull away with a light tug, clear the lot off the surface so nothing damp is left sitting on the compost.
Then move the pot somewhere cool, dim and dry. Fifty to 60F (10 to 16C) with no water at all, for four to eight weeks. Write the date you stopped watering on the label, along with the date you plan to restart. A bare pot in a shed is the easiest thing in a garden to lose track of, and bulbs left dry for many months rather than weeks come back weak.
If a plant never fully collapses and instead just thins for a couple of months, that is fine and there is no need to force it. Force a rest deliberately only when a plant is clearly running down, with smaller leaves and no flowers cycle after cycle. That reset works far more reliably than trying to feed a tired plant back into flower.
Five notes that make the next cycle predictable
Because this plant runs on a drifting cycle rather than a calendar, a written record is worth much more here than it is on something that flowers every spring. Five dates per pot per cycle is enough to plan the next one precisely instead of watching and waiting.
Record the restart date, the date the first leaf opened, the date the first flower opened, the date yellowing began in earnest, and the date you stopped watering for the rest. From those you get three numbers you will use constantly: the lead time from restart to first leaf, the lead time from restart to first flower, and the total length of the growth phase. Knowing that your plant flowers eleven weeks after a restart lets you time it to be in bloom for a particular part of the year.
Alongside the dates, record two facts: how many bulbs went back into the pot at the last refresh, and where the pot stood during the cycle. Bulb count tells you when to thin, because a pot that has gone from eight bulbs to forty is due. Position explains almost every difference in performance between one cycle and the next, and it is the detail nobody remembers having changed.
Photograph the pot from the same standing point at the first flower of each cycle. Comparing two photographs taken at the same point in the cycle shows density, color and stalk length changes that no written note captures, and it takes five seconds.