As July 4th quickly approaches I thought this would be a most timely thread.
"A pinch in time makes your Chrysanthemums
Pinching back, the gardener's term for the very simple operation of removing the growing tip or top of the main stem or stems of a plant in order to induce the development of side branches lower down is an old practice and a very simple one.
With few plants in the garden, and perhaps with no other perennial, is pinching back more essential than it is with Chrysanthemums...
To get stocky, self-supporting plants, with more bloom, pinch out the growing tips...and new growths again (at black lines)...getting bushy, well-rounded plants which support themselves, instead of the tall, lanky growth characteristic of many varieties when left to themselves...
The stronger lateral, or side, branches which result from this pinching will grow upward, and these, when 8 to 10 inches long, are pinched out at the tips. Plants that still show a tendency to grow tall and leggy may be pinched again up until mid-July to August. Later pinching will delay the formation of flower buds. The number of pinchings desirable will vary with the time of planting, the variety, and season. The more rapid and luxuriant the growth, the more pinching." http://www.organicgardentips.com/how_to_grow_mums.html
"Pinching chrysanthemums yields compact, bushy plants with more blooms. "Pinching" simply means removing the tips of new growth, thereby stimulating the chrysanthemums to send out side-shoots. Start in the spring when the new growth has reached 4-6" in length. Thereafter, every 2-3 weeks, pinch the center out of any more growth when it reaches 6". But stop pinching chrysanthemums around the beginning of summer, or else bud formation won't occur soon enough to ensure flowering." http://landscaping.about.com/od/landscapecolor/p/chrysanthemums.htm
"...to get the best display of flowers this fall, you should pinch the plants back to create more branching and more flowers.
Mum plants flower in response to both day length and temperature. Most cultivars begin to develop flower buds when days are less than 12 hours long and generally continue to flower for a period of 6-8 weeks...
The first pinching should be done when the plants are about 6 inches tall (about mid-June in central Indiana) to induce lateral branches. As soon as these lateral branches become 6 to 8 inches long (about mid-July), they, in turn, should have their tips removed to induce more branching. This procedure may seem drastic, but the results will be bushy, well-shaped flowering plants. After the July pinch, let the plants' foliage take its course--pinching too late can reduce the number of flower buds." http://www.hort.purdue.edu/ext/pinchmums.html
"Mums must be pinched back during the spring and summer to encourage lateral branching and sturdy, compact growth. Unpinched mums will bloom but the plants will grow more open and develop fewer flowers.
I begin pinching mine in spring as soon as new shoots are 3 to 4 inches long. To pinch mums, grasp the growing tip and the first set of leaves on each shoot between your thumb and forefinger and nip them off, removing about 1/2 to 1 inch of stem. The plant will look neater if you pinch above a node, but this is not absolutely necessary. Pinched-back plants will push out new stems from these nodes.
Pinch again when the stems reach 3 to 4 inches long. The exact date for the last round of pinching depends upon your climate and the type of mums you are growing, but I make my last pinch in mid-August.
A few weeks after the last pinch, mums will begin to develop flower buds. If you want fewer but larger flowers, pinch out all but the center flower bud; if you want lots of flowers and don't care about the size, allow all of the buds to remain." http://www.garden.org/regional/report/arch/inmygarden/1901
"Timing of the pinch varies with plant growth. Pinching should occur after the plants have become established and actively growing... Remove around 1/2 inch of growth. A second and third pinch may be required on the plants. Second and third pinches should be done after 3 to 4 inches of new growth has developed on the breaks, removing around 1/2 inch of growth. Generally in the Southeast, the last pinch date should be between July 10 and July25 and up to a week earlier in the northern US. Pinching too late will delay flowering." http://www.ces.ncsu.edu/depts/hort/hil/pdf/hil-506.pdf
"To grow stocky, heavy-flowering plants, pinching back the growing tips is essential. Pinch off the top 1 to 2 inches of growth when taller varieties are 6 to 9 inches high and shorter varieties are 4 to 5 inches high. Repeat every three to five weeks until early July, more frequently with the most dwarf varieties. In warm climates, where mums begin growing in March, plants are usually ready for their first pinch by May 1. But in most of the country, pinch them the first time on Memorial Day, and the second time on the Fourth of July." http://www.doityourself.com/stry/marvelousmums