The Dahlia: September's Splendor
The dahlia plants in the garden have been blooming since August. The heat, droughts, and hot sun this year have faded the flowers, created open and green centers, and have otherwise disappointed. But then comes September, and just the opposite. The plants sprout taller and deeper with blooms that are brighter, flashier, and often glow with secondary colors.
When I first started growing, I remember that Kidd's Climax, a large light blend, mostly pink during the summer, would sparkle with streaks of yellow-gold. In our area of the Mid-Atlantic, September is the month for shows, because the blooms are at their best.
On the west coast, in years without tragic forest fires, August is the month of dahlia splendor.
Come October and shorter hours of daylight, the flower stems will lengthen, and more and more blooms will have open centers, encouraging sex with the pollinators. For those so inclined some of the blooms will form seed pods and develop seeds that can be kept in paper bags until Spring. You can easily become a hybridizer. Dahlias have multiple sets of chromosomes; each seed is a free lottery ticket.
Debunking a Myth: You do not have to wait until frost to cut back and dig dahlia plants. Four months from planting allows enough time for the tubers to mature. Digging in the snow or cold is no fun. In some parts of the country you can try leaving the cut plants in the ground, covering the stalk with foil and adding six or more inches of mulch. Much depends on the drainage around the plant. Soggy soil encourages tuber rot so this is probably not a good strategy in wet areas.
Most of us no longer have a root cellar. A master grower I knew stored cut dahlia clumps in plastic bags filled with more than half vermiculite. While 50◦ F is ideal, he just left them in the basement until March. See the links below for details on lifting your tubers and storing them.
This is September in a time of COVID. Just enjoy the dahlias.