Gadenin日本語Get the appWhat a pinch actually does to the plant
A chrysanthemum shoot grows straight up from a single growing tip, and while that tip is alive it suppresses the buds in the leaf joints below it. Remove the tip and that suppression goes with it: within two weeks the top three or four leaf joints each push out a side shoot. One stem becomes four.
Do it again to each of those four shoots and you have sixteen. Because every one of those shoots will end in flower buds, the pinching is what decides how many flowers the plant carries. An unpinched chrysanthemum makes a handful of tall bare stems that flop outwards under the weight of a few large blooms at the top. A pinched one makes a dense, self supporting dome covered in bloom, from exactly the same plant.
The second thing a pinch does is shorten the plant. Each pinch resets the height and the resulting shoots start lower down, which is why a well pinched plant needs far less staking. This is the whole reason nurseries can sell a knee high dome in a pot: theirs is done with a growth regulator, but pinching gets you most of the way there for nothing.
The two or three pinches, in order
Pinch with your fingers rather than pruners. You want to take out just the soft growing tip and the top inch or so of stem, above a pair of healthy leaves. Snapping it out with a thumbnail leaves the cleanest break and does not spread disease between plants the way shared blades can.
The whole program runs through early and mid summer and finishes at midsummer. The pinches are timed off the plant, not the calendar: each one waits for the shoots from the previous pinch to reach a workable length.
- First pinch when the plant is 6 to 8 in (15 to 20 cm) tall Take out the top inch (2.5 cm) of the single main stem, above a pair of leaves. The plant must be clearly growing and established first; do not pinch a plant still recovering from being moved.
- Second pinch when the new side shoots are 6 in (15 cm) long Roughly two to three weeks later. Pinch the tip out of every one of the new shoots, not just the tallest. Missing some leaves you with a lopsided plant that never evens out.
- Third pinch only if midsummer is still a few weeks away Same again on the next generation of shoots. This is worth doing on vigorous, early started plants and is a mistake on a plant that was planted late.
- Stop at midsummer and leave the plant alone From this point every tip you remove is a tip that would have carried flowers. Let the shoots run on and put your effort into water, potassium feed and support instead.
- Remove any shoot that outruns the rest If one stem shoots up well above the dome after you have stopped pinching, cut it out at the base rather than pinching it. It will not catch up in time to flower with the others.
Nothing is gained by pinching harder than this. Taking out several inches of stem instead of one removes leaves the plant needs and delays the regrowth by a week or more each time.
Why the stopping date matters more than the starting date
After a pinch, the new shoots need roughly six to eight weeks of growth before they are mature enough to respond to the shortening nights and set buds. Buds are initiated from late summer onwards, so any pinch made after midsummer removes tissue that was about to become flowers and replaces it with soft shoots that will not be ready in time.
The result of a late pinch is a plant that flowers weeks behind everything else, into the frosts, with small and often damaged blooms. It looks like a light problem or a feeding problem and it is neither. If you inherit a leggy plant in late summer, the right answer is to leave it, stake it, and pinch it properly the following year.
| When you pinch | What the plant does | Flowers you get |
|---|---|---|
| Never | Few tall single stems, flops outward | A handful of large blooms, mostly at the top |
| Once, in early summer | Three or four stems, moderate height | Noticeably more, plant still needs staking |
| Twice, early and mid summer | Twelve to twenty stems, compact dome | The best balance for most garden plants |
| Three times, finishing by midsummer | Dense low mound, many thinner stems | Most flowers, individually smaller |
| After midsummer | Soft late shoots with no time to mature | Late, few, and often lost to frost |
Disbudding is a separate decision
Pinching sets how many stems there are. Disbudding sets how big the flower on each stem is. At the end of each stem you will find a fat central bud surrounded by a ring of smaller ones. Rub out the ring and the stem puts everything into the single central bloom, which is how exhibition sized flowers are produced. Leave them all and you get a spray of many smaller flowers on that stem.
For a garden display, leave them. A pinched plant carrying full sprays gives the covered mound effect that people actually want from a chrysanthemum, and it flowers over a longer period because the buds in a spray open in succession. Disbud only the few stems you intend to cut for a vase.
Record the dates of your pinches each year alongside the date the first flower opened. After two seasons that record tells you exactly how many weeks your own plants need between the last pinch and flowering, which is the only reliable way to time the third pinch in your own garden.