Asters Leggy? Pinch plus Cut Back for Bushy Plants
Asters leggy by fall usually grew tall plus floppy without any pinching or cutting back. The University of Washington Miller Library notes cutting asters back by half in mid June gives a mounded plant plus delays flowering by only a few days. NC State Extension notes taller plants may need staking.
The short answer
Asters leggy by fall respond to pinching or cutting back. The University of Washington Miller Library advises pinching new growth until early July or cutting plants back by half in mid June. NC State notes pinching gives a bushier plant. Stake tall types plus divide clumps that go bare in the center.
Why are my asters so leggy?
NC State Extension notes New England aster forms large bushy clumps 3 to 6 feet tall plus taller plants may need staking. Without pinching, stems stretch tall plus can flop.
| Factor | Target | Source |
|---|---|---|
| Pinching | Small bits of new growth until early July | UW Miller Library |
| Cutting back | By half in mid June | UW Miller Library |
| Bloom delay | Only a few days | UW Miller Library |
| Sun | Full sun | NC State |
| Short cultivar | Purple Dome, 2 feet | NC State |
Source: UW Miller Library plus NC State Extension.
When should asters be pinched?
The UW Miller Library advises pinching new growth like mums until the first of July or cutting plants back by half in mid June. Outer stems can sit lower than inner ones for a mounded shape.
Do tall asters need staking?
NC State Extension notes taller New England asters may need stakes. Ask Extension points to staking for asters that flop plus advises pinching primary buds from mid spring the next year.
How to: step by step
- Note which asters grew tall last year.
- Pinch small tips of new growth from spring.
- Or cut plants back by half in mid June.
- Cut outer stems lower than inner ones.
- Stop pinching by the first of July.
- Stake tall types before they fall.
Troubleshooting
Tall, bare lower stems: no pinching. Cut by half next June.
Plant flops open: tall type. Stake it plus pinch next spring.
Bare center in clump: aging plant. Divide in spring.
For more on outdoor growing see the effects of environmental stresses on weed plants, fertilizer and compost for growing outdoors plus underwatering cannabis. Kind Seed Co also stocks cannabis seeds.
Sources
- On pruning asters, University of Washington Elisabeth C. Miller Library
- Purple aster stems only in the middle, divide?, Ask Extension (Extension Foundation)
- Symphyotrichum novae-angliae (New England aster), NC State Extension Gardener Plant Toolbox
- Dividing perennials, University of Minnesota Extension
FAQ
Does pinching delay aster flowers?
A little. NC State Extension notes pinching stems in spring delays blooming plus creates a bushier plant. The UW Miller Library notes cutting asters back by half in mid June tends to delay flowering by only a few days while giving a much prettier plant with blooms nearer the base.
Can asters be cut back in July?
Aim to finish by then. The UW Miller Library advises pinching asters like mums until the first of July or cutting them back by half in mid June. Later cuts risk removing flower buds on fall blooming types, so plan the work for late May through June.
Are there short aster varieties?
Yes. NC State Extension lists Purple Dome, which grows only 2 feet tall with many purple flowers plus Honeysong Pink at 2.5 to 3 feet. Purple Cloud reaches 6 feet. Choosing a shorter cultivar cuts down on staking plus pinching for a front of bed spot.
How often should asters be divided?
Not often. Ask Extension notes a one year old aster rarely needs dividing plus it likely will not for a couple of years. University of Minnesota Extension notes smaller blooms, a bald center or the need for staking are signs it is time. Divide fall bloomers in spring.
Why is my aster bare in the center?
Ask Extension describes asters that fall open plus leave only stems in the middle. It advises staking plus a program of pinching primary buds from mid spring through early summer the next year. University of Minnesota Extension notes a bald center can also signal a clump ready to divide.
