Coping with the drought
Knysna has had water restrictions for many years, not only due to drought. Our population has expanded exponentially and we have decaying infrastructures, poor maintenance plus inadequate planning for the future.
Having lived through several droughts in my gardening life, the one we are experiencing in Knysna at the moment is probably the worst. Rainfall figures reflect the dire situation: November 7.6mm (70-yr av. 63mm), December 21.1mm (70-yr av. 58mm)and it doesn’t look so good for January either. And our ‘drier’ months are still to come……..
Driving along the Lagoon Road, seeing Buddleja saligna wilted, Aloe arborescens blackened by sun scorch, and Yellowwoods showing signs of stress is indeed a very disturbing sight. More worrying is the how Alien Invasive Species seem to flourish, outcompeting the indigenous flora for any available moisture. This is a wake up call to all residents of Knysna to take stock what is growing in and around their properties and to take action.
We have all been indoctrinated to garden with indigenous plants, as these plants are more adapted to local conditions and supposedly drought hardy: however, a very different scenario is developing. Many indigenous species are dying off, the biggest percentage being plants from other regions or introduced hybridized species.
What gardeners do not realise is that most indigenous species have very specific soil & climatic requirements. If your Protea species have died, it is not because they are not hardy; they just hate being planted near hot reflecting walls, or in enclosed areas. Remember Proteas grow naturally in mountainous or hilly areas where the cool prevailing winds normally carry some moisture; the same applies to Ericas growing on clay stratas with continuous seepage – they will not survive growing in ‘alien’ conditions without regular watering.
Even succulents seem to struggle as they are shallow rooted, and once the roots are damaged by drought they become woody and unsightly: it is best to propagate new plants by taking top cuttings while there is still sign of life. If you are looking for indigenous replacement plants, the following are coping well at the moment: Barleria sp., Plumbago, Zygophyllum morgsana (skilpadbos) Coleonema (Confetti bush), Carissa (num-num)
The old stalwarts, alas exotic, will give colour when the landscape is drab: Cistus, Escalonia, Viburnum, Westringia, Hibiscus, Abelia, Bougainvillea, Frangipani
Impacts of a Drought:
A drought is any gardener’s worst nightmare. When the days are incessantly hot and windy, it affects your landscape in a variety of ways. There’s nothing you can do to prevent a drought, but there are some strategies you can enact to help minimize the effect it has on your garden.
The initial symptom of drought stress on trees and shrubs is a marginal scorching of leaves, and in some cases wilting of entire plants. Yellowing on evergreens may also occur. When irrigated, by either irrigation or rainfall, most plants will recover, but it can take most plants several years to fully recover from drought.
The season following a drought, plants may show reduced shoot and diameter growth, smaller or fewer leaves, and varying degrees of dieback. Weakened trees and shrubs can also be expected to have more disease and insect problems for several years to come. Evergreens especially, may brown, drop leaves and die suddenly.
Plant survival tips:
- Remove plants in crowded beds or low-priority plants competing for soil moisture
- Mulch, mulch, mulch! Mulching is one thing you can do to help your plants. It is estimated that three quarters of the rain falling on bare soil is lost to plants through evaporation and runoff. Both of these are reduced up to 90% by adequate mulch. Mulches help conserve moisture and keep the soil cooler. Use compost, wood chips, bark nuggets, shredded bark mulch, shredded leaves, or any other organic material to cover the surface of the soil. Apply mulch to a depth of 50 – 70cm
- Infrequent deep watering encourages deeper root growth, and results in plants with greater drought tolerance
- Fertilizer application is not recommended. When soil moisture is low or temperatures are high, little benefit will be realized from fertilizer applied to plants. Without adequate water, fertilizer can burn your plants
- Do not prune except to remove dead or diseased branches. Excessive pruning will stimulate new growth that will not be drought tolerant and, in addition, may not harden off before the dormant season sets in.
- Plants that are healthy are better able to resist attack by insects and diseases. Therefore, if plants are to withstand a drought, they must be kept as healthy as possible. It is important to monitor for insects and diseases and manage them before they take hold