Caring for dahlias in September

5 tips that will help extend the dahlia blooming season

1. Deadheading

Pruning spent flowers will boost more flowering. Your dahlia should use its energy to produce floral buds instead of seeds

How to:

  • Spent flowers have a pointy shape while the coming floral buds are round and somewhat leaning down.
  • Cut with a sharp scissor or pruner up to the next lower set of leaves.

2. Fertilizing

The dahlias should provide you with ample blooms until the first frost. Why not help them with a liquid fertilizer such as the Jack’s Classic Blossom Booster 10-30-20. Apply diluted in water with a siphon hooked to your hose (available for about $20 at a garden center) every 2 weeks. If not available, a tomato fertilizer could be used instead, such as 10-20-20.

Some plants may never bloom for different reasons but still produce healthy tubers for next year. If the plant seems healthy, it could be a late bloomer.

3. Diagnosing foliage problems

If the foliage is showing signs of chlorosis (yellowing of part of the leaves), it can be a sign of mineral deficiency. The bottom leaves becoming yellow with the veins staying green, it is probably a magnesium deficiency. Try spraying the leaves with Epsom salt, 1 tablespoon per gallon, preferably dissolved first in warm water and then cooled down.

Various pests, or diseases, including viruses, may cause dahlia leaves curling. Examine first flowers, leaves and stems to check for thrips, mealy bugs or white flies, and if so, treat with a low impact pesticide. If insects do not seem the culprits. try first providing ample watering during drought. If the problem persists, suspect a disease or a virus and plan having to discard the tubers at the end of the season.

4. Checking your labeling

Even if you do not bother with variety names, it is helpful to note the color, shape and height of your dahlias while they are blooming. This will prove useful when you collect the tubers (for those in zones 6 and colder), prepare for winter storage and plan planting in the Spring, Take photos of both your blooms and their labels.

5. Finally, enjoying!

Remember that the more you cut dahlias, the more you will get dahlias. If you are cutting the flowers, the best time to do so is in the morning while it is cooler outside, athough as much as the temperature switches to Fall, it can be safe to do it at other times. Condition your blooms in a bucket of cold water for at least 30 minutes before arranging them. And be sure they never lack fresh water in a vase to enjoy them for 4-7 days.

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