Dahlia 'City Lights Purple' is a compact, tuberous perennial that produces rich purple semi-double blooms on tidy, bushy plants suited to containers, front borders, and mixed beds. It belongs to the Asteraceae family alongside sunflowers and zinnias, and is bred from species native to highland Mexico and Central America.
Plant tubers after the last frost in rich, well-drained soil with full sun. Water consistently during active growth but allow the soil to dry slightly between deep waterings to prevent tuber rot. At the cooler edge of its range, a thick mulch layer over the crown provides winter protection; in zones 10–11, plants may remain semi-dormant through mild winters. Deadhead regularly to extend the blooming season well into fall.
The tubers of dahlia species were cultivated as a food crop by indigenous peoples of Mexico before dahlias reached Europe as ornamentals. Petals of garden dahlias are edible and carry a mildly bitter, slightly starchy flavor used in salads and as edible garnish.
Growing dahlias? Read the Dahlia Growing Guide - pinching and disbudding for more stems, the flower forms, and the winter tuber storage method, timed to your frost dates.Powdery mildew
White or grey powdery coating on leaves - usually starting on older growth in humid conditions or when nights cool.
Improve air circulation by thinning plants. Apply neem oil or potassium bicarbonate spray at first sign. Avoid overhead watering.
Botrytis (grey mould)
Grey fuzzy mould on petals and stems, worst in cool wet conditions.
Remove affected parts immediately. Improve air circulation. Avoid overhead watering. Apply copper fungicide if severe.
Mosaic virus
Yellowing, mottled, or distorted leaves. No cure - spread by aphids.
Remove and destroy infected plants. Control aphid populations to prevent spread. Do not propagate from infected tubers.
Fusarium wilt
Sudden wilting, brown streaks in stems, yellowing leaves. Affects sweet basil varieties most.
No cure. Remove and destroy plants. Do not replant in the same spot for 3+ years. Choose resistant varieties.
Tuber Rot
Stored or in-ground tubers turn soft, brown, and mushy, often with mold growth. Affected tubers fail to sprout in spring.
Lift tubers only after foliage dies back, cure them in a dry airy spot before storage, and store in a cool dry location with breathable packing. Discard damaged or soft tubers and avoid waterlogged soil during the growing season.
Crown Rot
Lower leaves yellow and wilt; the base of the rosette turns brown and soft, sometimes with white fungal threads at the soil line. Plants collapse in wet conditions.
Remove and destroy affected plants. Improve drainage and avoid overhead watering. Do not mulch directly against the crown. Space plants for airflow and avoid replanting in the same wet spot.
Verticillium Wilt
Lower leaves yellow and wilt, often on one side of the plant, with brown streaking in the stem and crown tissue when cut open. Plants are stunted and decline over the season.
Remove and destroy affected plants. Avoid planting in soil that has grown infected tomatoes, peppers, or other susceptible crops. Rotate beds and improve drainage; there is no cure once a plant is infected.
Aster Yellows
Deformed, greenish flowers, stunted growth, and yellowed foliage. Flower centers may produce tufts of leafy growth instead of normal petals.
No cure. Remove and destroy infected plants immediately to stop spread. Control leafhoppers, which transmit the disease, and remove nearby weed hosts.