A summer to fall flower, dahlia is a genus of tuberous plants that belong to the Asteraceae family. It is named after the Swedish botanist Anders Dahl (1751 - 1789). Its plants are easy to grow and yield beautiful blooms. To ensure good blooms, one needs to ensure good care while purchasing, planting, and storing them.
Native to Mexico, Central America, and Colombia these flowers have over 36 species and countless numbers of hybrids developed for their use as garden plants. This decorative flower grows on tuberous perennial bushy plants that range from 12 inches to nearly 8 feet in height. This plant's foliage is deep to bright green. It has lobed leaves on hollow stems whose end flowers are borne mostly alone. However, clusters have been found too. The size of the flower; miniature to really large ones depends upon the cultivar planted. With over a hundred varieties available, one will definitely be spoiled for choice when it comes to choosing colors.
Dahlia can be propagated negatively (division of tubers, stem cuttings, grafting, leaf cuttings, and through tissue culture) or from seeds. Division of tubers is the easier way to sprout new plants. Additionally, the bulbs for different varieties are more easily available than seeds.
Growing Dahlia Bulbs
This plant bulbs from April right through May, when the temperature approximates between 50 to 60 degrees. It can be grown in flowerbeds or in pots. Its plants need a sunny location for their flowers to come true. Minimum 6 - 8 hours of direct sunlight is required. However, in extremely hot areas 3 - 4 hours will suffice. These bulbs do very well in humus rich soils that have tilled deep and amended with sand or peat moss. This makes them well-drained. Compacting soil prevents them to sprout well as ventilation gets blocked. The soil's balance should be maintained at pH level 6.5 - 7 (slightly acidic).
Plant the bulbs about six to eight inches deep in a hole with a handful of organic compost and bone meal. Place them with the 'eye' of the tuber facing up (eye is the point of the tuber from where the plant grows). Depending upon the variety, space them between two inches to a feet apart. Stake the bulbs either with canes or even tomato cages. Water as per need but never in excess as the tuber may begin to rot. In most cases, rain showers are adequate to get the tubers to sprout. Once they sprout, just ensure enough water is supplied especially for warmer climates.
Nitrogen-based fertilizers must be applied sparingly, and those with a high percentage of potassium and phosphorous are more recommended, such as a 5-10-10 or 0-20-20. Too much nitrogen will promote excessive foliage growth. In the longer run, too much nitrogen damages bulbs while in storage. As the plant begins to grow, pinch central leader to promote lateral and bushier growth. Once the flowering starts, keep deheading the dead ones to encourage continuous flowering. Mildew and leaf spot are common fungal infections found in these plants, and besides them slugs and aphids too routinely attack them. Spray specific-to-problem germicides early in the morning or late in the day.
Care to be taken
Knowing how to care for dahlia bulbs is essential for their next year's bloom. Once the plant wilts and falls to the ground naturally, dig with a spade about a foot away from the stem in a circle to loosen the soil and tuber roots. Do not pull each tuber separately (it can be sheared later on), and pry the whole clump with the intact stem. Brush away all the soil stuck to the tubers, and air dry the entire clump by hanging it upside down in a dry place for a couple of days. Do not let them dry out or freeze. Treatment with powdered garden sulfur fungicide can also be considered to prevent rot during storage. Layer them in crates or cardboard boxes amidst dampened peat moss, sand, or newspapers. Last but not the least, keep a routine check on them.
Dahlia bulb care begins with proper storage and culminates with a remarkable flower show.