Gareth Carter: Hot, hot, hot – Making your garden thrive in the heat

The use of mulch stops the sun having direct contact with the soil and reduces water loss directly from the soil. Photo / File

Food and water are the two critical factors for making our plants and gardens grow healthy. It is at this time of year when many underestimate how much water some plants need to thrive. The hot sun each day at this time of year not only takes water from the plants through their leaves but the surrounding soil loses much moisture too.

When watering it is important to check how deep the water has gone into the soil. The sprinkler on for a couple of hours usually only gives water to the top few centimetres of soil and is not enough. For new tree and shrub plantings made over the past six months I recommend the hose on a trickle overnight every two to three days to ensure good success. This can be achieved using soaker hoses or drip irrigation systems for larger areas where there are more than a couple of plants that need this treatment.

The use of mulch stops the sun having direct contact with the soil and reduces water loss directly from the soil and creates a moister soil for those plants growing in it.

We in Whanganui are very lucky to have a plentiful town water supply that means we do not have water restrictions, so water away happily (but wisely) and you can have a lush garden!

On some parts of our property it is advantageous to grow drought-hardy plants such as succulents. The distinguishing feature of succulents is their ability to withstand long periods of drought. This is due to the presence of water-storing fleshy tissue in the stems, leaves or roots. Cacti have structures called areoles – cushion-like growths on their stems from which the spines, hairs, flowers and shoots develop.

Succulents and cacti display a unique variety of size, shape, colour and texture. Many flower only for short periods and produce large brightly-coloured flowers, while others flower for longer periods, producing an abundance of exquisite flowers. They fulfil the need for tidy and colourful plants in various areas around the home for many years, with little maintenance compared with other plants.

In Whanganui's temperate climate many succulents and cacti can be grown as indoor or outdoor plants. Hardier species can make a beautiful garden display and in hot dry spots there is an opportunity to create an outdoor desert garden. Whether you grow them as single specimens or as a diverse group, their tolerance of dry conditions makes them ideal for containers, both indoors and out. They often make ideal pot plants for a sunny windowsill, balcony, deck or patio.

When growing in pots, use a specialist potting mix such as 'Yates Thrive Succulent & Cacti Mix' - they will give great results. An addition of a slow-release fertiliser such as 'Ican Slow Food' each year will ensure continued health and growth of these plants.

Growing Indoors

Many succulents and cacti will thrive in containers and indoors if provided with warm, bright light. Use small pots for individual plants or large bowls for planting a selection of compatible species together. Gloves should be worn when handling prickly or spiny plants such as Agave, Aloe and Opuntia because their sharp spines can easily become embedded in your fingers if you brush against them and be quite painful. The use of barbecue tongs is also quite useful when handling them!

Bowls can be very effective for growing succulent and cacti plants indoors. One or two plants with a columnar habit can provide the focal point of the bowl or a leafy succulent such as the Jade Plant (Crassula ovata) as the main plant. The rest of the bowl can be filled with small plants such as Echeveria and Lithops Succulents - they are really fun to grow in containers because they don't complain or suffer when neglected, like most other pot plants do. Many can be grown for longer before they need repotting.

Lithops

This unique succulent is commonly known as Flowering Stones or Living Stones. This is because their shape, size and colour looks like that of small pebbles or stones. They occur naturally in large areas of West Africa, where little rain falls. The body of the plant is made up of two fleshy leaves that are fused together. These store water, which enables them to live in areas of extreme drought and go for a number of months without water.

In cultivation, they can be grown indoors or out. They make an ideal easy-care houseplant as long as they receive four to five hours of direct sunlight each day. A north- or west-facing windowsill is ideal.

Outdoors they need a free draining spot to cope with the higher rainfall we have here than in their naturally occurring environment. They will cope with this fine as long as the drainage is good. If you are concerned, the raising of an area with sand, gravel or cacti and succulent mix will facilitate good drainage.

Lithops have a seasonal growth habit and will produce a new set of leaves each autumn. In the natural habitat, a period of autumn rain will instigate both growth and flowering too. Spicy sweetly scented yellow or white flowers are generally produced each autumn from when the plant is three to five years old.

Outdoor Plantings

Attractive collections of succulents and cacti grow successfully outdoors. Remember, however, that few succulents tolerate excess moisture and virtually all require good drainage. They grow well in raised beds where water drains away freely and easily. Succulents are great on the sand country, which we have much of around Whanganui.

Opuntia, Sedum and Sempervivum are among the hardiest. With sharp drainage and good hot sun in summer a number of desert species of succulents and cacti will withstand cold winter temperatures.

Heavy frost is generally the biggest enemy for succulents. A heavy frost can burst the cells in the fleshy leaves of succulents which can turn the plant into a brown, unattractive mush. Most of Whanganui has a temperate climate, which means this is not an issue.

When growing non–succulent and succulent plants together remember to choose plants that have similar needs for light, soil type and watering. Annuals such as Portulaca and Livingstone Daisies are suitable for planting outdoors among succulents and cacti.

Gareth Carter is General Manager of Springvale Garden Centre