Gadenin日本語Get the appWhat a normal flowering season looks like
An established plant sends up flowering stems from early summer, opens its first flower in midsummer, and carries flowers for eight to ten weeks into early autumn. Each individual flower lasts a long time, often three weeks or more, because the petals hold while the central cone keeps developing. That long individual life is why a modest number of stems still reads as a long display.
The petals start out held horizontally and gradually drop back and downwards as the flower ages. That reflexing is normal ageing, not stress or heat damage. The cone darkens and stiffens at the same time, and by the end of the season it is a hard bristly knob that will stand all winter.
The four reasons a plant will not flower
Almost every case of a coneflower that makes leaves and no flowers comes down to one of four things, and they are easy to tell apart once you know what to look for. Work down the list in order, because the first is by far the most common and costs nothing to fix.
| Cause | What you see | What to do |
|---|---|---|
| Too young | Healthy low rosette of leaves, no stems at all | Wait. Seed-raised plants usually flower in their second year, sometimes their third |
| Not enough sun | Tall thin stems leaning one way, few buds, larger than normal leaves | Move it in autumn to a spot with six or more hours of direct sun |
| Too much nitrogen | Lush dark green leaves, thick soft stems, flowers small or absent | Stop feeding entirely for a season and remove any deep mulch over the crown |
| Crown damaged or rotting | One side of the clump collapses, stems pull out easily and are brown at the base | Lift and check the crown; if soft, the plant is finished and the site is too wet |
Deadheading, and when to stop
Through the first part of the season, cutting spent flowers off does help. Removing a faded flower before its seed sets pushes the plant to open side buds it might otherwise have skipped, and it keeps the clump looking sharp. Cut the whole stem back to just above the next healthy leaf or side bud rather than snipping the flower head off and leaving a bare stick.
- Deadhead through early and midsummer Follow each faded flower down the stem to the first pair of healthy leaves with a bud in the joint, and cut just above it. This is where the next flowers come from. Doing this every week or two through the first half of the season noticeably extends the display.
- Stop deadheading in late summer Once the days are shortening and new buds are no longer forming, deadheading gains you nothing and costs you the winter structure. Leave every flower from this point on to set seed and go over on the stem.
- Leave the cones standing all winter The dark cones on stiff stems hold snow and frost beautifully, and finches and other small seed-eating birds work them over through winter. Cut the old stems down in late winter or early spring, just before new growth pushes up from the crown.
Leaving the seed heads also means self-sown seedlings will appear around the parent. That is usually welcome, but seedlings from a colored plant will not look like their parent, so pull the ones you do not want while they are small.
Be honest about the colored forms
The plain purple-pink kind, with its slightly untidy drooping petals and orange-brown cone, is a tough long-lived plant that settles into a border and stays there for many years. The bright modern breeding, the oranges and reds and yellows and the double pompom types, is a different proposition. Those plants are complex hybrids, they are often propagated by tissue culture and grown fast under glass, and a great many of them are short-lived in the open garden.
The usual pattern is a spectacular first summer, a thinner second summer with paler flowers, and nothing at all in the third spring. Sometimes the color itself fades towards a muddy pink as the plant ages. This is not something you did wrong, and no amount of care reliably prevents it. Treat those plants as a two- or three-year investment, put them where you will not mind replacing them, and build the backbone of the planting from the plain species so that the border does not empty out.
What to write down about flowering
Record the date the first flower opened on each plant and the date the last one faded, every year. Over three seasons that pair of dates tells you more about a coneflower than anything else you can note: a plant that starts later and finishes earlier each year is losing light or losing vigor, and you will see it in the numbers before you see it in the border.
Note which plants were bought in color and which are the plain kind, and keep that note attached to the position rather than to a label that will be lost. When a gap appears in the third spring you will want to know whether the plant that died there was one of the short-lived colored forms or something that genuinely failed.