The delight of dahlias: Tips for planting and caring for these beauties

As a native of Mexico, the dahlia is a subtropical plant that needs humus-rich soil, constant watering, and regular feeding. Given those things, the dahlia will delight you with its texture and layers if you follow these tips.

Since dahlias are heavy feeders, in the fall you will need to dig into the bed a rich dressing of dried or well-rotted manure, compost, or other suitable organic material.

Sprinkle on a topdressing of 100 grams (a third of a cup) of bone meal for each square metre (three feet square).

To allow frost and air to penetrate and break down the added materials, do not smooth down the ground.

If the soil is not rich, apply a balanced organic fertilizer, according to package directions, monthly after growth begins.

When potted plants or tubers are first planted, watering represents a danger to them — it can cause the tubers to rot. It does the roots no harm to search for moisture.

• For the best results, give dahlias a great deal of moisture as they approach their flowering season. In dry spells the plants should be watered freely, whether or not they are coming into bloom.
• When weather is hot and sunny, water every five days or so on heavy clay soils. Lighter soils dry out more quickly, and the plants should be watered about every three days.
• Use an automatic sprinkler that throws a fine spray up high enough for the water to fall vertically on the plants, or a soaker hose laid through the plants.
• Either one will ensure that the area around the dahlias receives the required thorough soaking.
• If you use a can or hose, give about 12 litres (12 quarts) of water to each plant when they are 60 to 90 centimetres (25 to 35 inches) apart; use less if they are set closer together.

When the plant is about 30 centimetres (12 inches) high, put a three-centimetre (one inch) layer of mulch around the base but not against the stem. This helps keep down weeds and retain moisture.

• Use wood chips, buckwheat hulls, cocoa shells, or clean, dry straw.
• If you mulch with grass clippings, do not use grass from a lawn that has been treated with a selective weed killer.
• Apply in thin layers, and allow each to dry before applying more.
• Do not mulch too early. Wait until the plants have grown to a height of 30 centimetres (12 inches).
• The ground should be moist when mulch is applied and well soaked immediately after.
• If weeds appear before mulching, remove them by hoeing, which will also keep the soil aerated.
• Do not cultivate more than three centimetres (one inch) deep.

Dahlias need support to prevent wind damage.

• Two or three weeks after planting, loop string around each stake 10 to 20 centimetres (four to eight inches) above the ground.
• Tie every plant, taking the string around the stem in a figure-eight pattern.
• Fasten the knot against the stake.As the plants grow, make further ties higher up the stem.
• Be sure the lower ties have not become too tight around the main stem.
• To prevent damage to the side growths, insert thin canes firmly in the ground — three in a triangular pattern around the main stake and about 25 centimetres (10 inches) from it — sloping out.
• Loop soft string around these canes to support the side growths.
•  Two or three weeks after planting, tie plants to stakes with soft string.
•  As the plants grow, add more ties. Check that lower ties are not too tight.
•  Support side shoots with soft string tied around three thin stakes.

While this may seem like a bit or work, these plants are worth the time and the effort. The gorgeous blooms will make it worth your while.