So you find yourself in the middle of the worst drought in living memory and your garden occupants are starting to sag, wilt and wilt. Which plants should be watered first and which plants should receive the main amounts of irrigation? You start to feel like the ruler of a third world country trying to divide your county’s meager budget between health care, the military, and education. Fear not, let me ease your worries with some dryness tips.
First to receive H2O
Recent plantings are top of the list for regular watering, if water is available. New plantings such as bare root trees or shrubs planted the previous fall/winter, newly planted perennials are also highly susceptible to drought damage. You see, these new plantings haven’t had much time to produce water-seeking roots, the type of roots that travel deep and wide for moisture. For this reason, we need to supplement the plants natural water supply. During a garden hose ban, recent plantings of summer annual litters such as Marigolds, Impatiens, Nicotiana, etc. must be considered as probable victims of the water war. If I had a limited water supply to divide between a Japanese maple and an annual litter, I’m afraid the maple would get the lion’s share and to hell with the litter. As a general rule, if the soil 5 cm (2 inches) below the soil surface is dry, it is time to water. Here is a short list of plants that can cope with a short drought once established… Brachyglottis, Corokia, Gleditsia, Halimiocistus and Hippophae.
Potted plants during a drought
Next on the list of water sinks are container plants, hanging baskets, and window boxes. Essentially, a container plant grows above the water table, with just the soil inside the container to provide the required humidity. If the moisture isn’t inside the container, I’m afraid the roots will have nowhere to go to quench the thirst of the plants. Again, if the compost 5cm (2 inches) below the surface of the pots is dry, it’s time to water, it’s up to the gardener to provide that water when needed. Try to provide a catch plate or tray under the containers, these “catchers” will contain any excess water that will eventually be absorbed into the compost. Be aware that terracotta and other porous container materials absorb a fair amount of water that the plant does not have access to. Here is a short list of potted bedding plants that can cope with a short drought once established… Arctotis, Lantana, Plectranthus, Portulaca and Zinnia
Vegetables and fruits in times of drought
Provide adequate amounts of water for moisture-hungry vegetables such as tomatoes, peas, onions, cucumbers, zucchini and lettuce. Insufficient water supplies will lead to miniature, shriveled and soft specimens. Fruit-bearing plants such as strawberries, raspberries, currants, apple trees and pear trees are also very demanding of moisture, especially during their fruit formation. Notice the amount of water in a strawberry or pear the next time you eat one of these delicacies. Water content figures of 70-90% are quoted for fruits and vegetables, regardless of the correct amount you need to supply this water during a drought. Plants growing in an exposed or windswept area will need a fair amount of supplemental water during a drought. Have you ever taken an invigorating walk on a windy day, arrived home, smiled at your spouse, kids or pet and realized your lips were cracked and chapped, ouch! This illustrates the harsh drying element of a strong breeze, plant leaves are constantly being dried and then re-moistened by ground water when available. During a drought, if this water is not present, the leaves will dry up, shrivel up and drop off. This is called leaf desiccation. Abundant watering will prevent this from happening.
Shallow roots and moisture lovers
Shrubs and trees that have shallow roots or are particularly fond of moist soil are at great risk during a drought. Shallow-rooted specimens include rhododendron, azalea, heather (Erica), hydrangea, and birch (Betula). Moisture lovers include Hosta, Ferns, Helleborus, Sarcococca, Fatsia and Camellia. If water is available, please allocate some to these plants. Climbing plants or wall shrubs planted near the walls of the house struggle for moisture at the best of times, mainly due to the rain shadow cast by the house itself. Don’t forget to water these wall hangings. Here is a short list of climbing plants that can withstand a short dry spell once established… Clematis Montana, Fallopia, Jasminum, Trachelospermum and Vitis.
Lawns during a garden hose ban
During a drought, the first part of the garden that people tend to water is the lawn. This is probably because lawns generally make up a good part of most gardens and these lawns tend to look burnt earlier than many plants. However, the lawn would be the last form of plant life in my garden to receive rationed water. Lawns are tougher than you think, a green lawn that turns brown due to lack of water will eventually come back after a few heavy downpours. The burnt piece is the foliage above the ground; the roots under the ground will stay tight and wait for the dry spell. Of course, lawns composed entirely of fine grasses will be significantly damaged by prolonged dry weather, but you shouldn’t worry if your lawn is sown with a utility seed mix (#2 or Manhattan mix).
How to apply water during a drought (if water is available)
I find that sprinklers waste the available water although rationed, instead I would choose hand sprinkling or seepage sprinkling. With hand watering, aim your watering can or hose at the base of the plant of your choice, water deeply at the rate of about 10 liters per square meter. Light watering will do more harm than good as it promotes surface rooting, which is easily damaged. On many dry soils, water applied directly will tend to run off the surface of the soil and away from the base of the plants, if this happens try the following tip. Sink a two liter pot filled with gravel at the base of the plant, water slowly into this pot and you will have no runoff problems. Seepage irrigation, also known as drip irrigation, is an effective and economical way to directly apply much-needed moisture. Most well-stocked garden centers will sell seepage pipes or porous pipes, which you weave between the plants in your flower beds and borders. This infiltration pipe, when connected to a water supply, slowly seeps water through small holes along the length of the pipe. It is extremely direct and effective.