How To Water Your Plants

 In Garden Design, News

I often get clients who are very confused about how and when to water their newly planted borders which has led me to write this blog. It is understandable that when you have spent your hard-earned money to create beautiful planting borders that you want your plants to establish. Here is some helpful advice to make sure you give your plants that best possible start.

As we all know, plants absorb water through the roots underground. This then travels through the stems to the leaves and it is the lost as water vapour through the pores of the leaves. These are known as stomata. This is known as the transpiration process. During humid weather the loss of water through stomata is less than during hot weather. Most water loss in plants occurs during windy weather. Wind is the enemy and it has a real drying effect on plants. If possible, time your watering to be late at night or when the sun has gone down. That way there will be less evaporation. Keep in mind that a 2litre plant will need less water than a 20litre plant.

My advice would be to avoid planting in hot weather. If it is raining heavily all day the likelihood is that you do not have to water. However, if it is a light shower or a very fine drizzle then you do have to water. Different plants have different watering requirements. Dahlias and Cannas are thirsty plants, but Lavenders are not. Your soil conditions will also determine how much water you give your plants. If you have very free draining, sandy soil then you will need to water for longer. However, if your soil is clay then your plants will not require as much water. Improving your soil with organic matter will help feed it and improve the water retentive qualities of your soil.

watering plants

Credit: Garden Gate Magazine

Give plants a deep watering at the base to encourage them to develop a deep root system. This will stop rocking and give you a stronger plant.


Newly planted trees take 3 to 5 years to establish. The more mature a tree, the more water it will require to establish. A young tree that has an 8 to 10 girth will require 90 to 100 litres (equivalent of approx. 10 watering cans) of water twice a week within it’s first year. During periods of drought or extreme heat this needs to be increased to 2 to 3 times per week. Bear in mind a lot of this is also dependent on the condition of your soil. If your soil is sandy and free draining, then you will need to increase the watering. It is important to encourage a tree to put its roots deep down into the ground. This can only be done by providing the trees with sufficient water. Its roots will stretch down into the ground in search of the water. This will also help anchor the tree into the soil and prevent rocking. In the second to fifth year if there is drought or extreme heat in the second year, water the tree 1 to 2 times per week.


Newly planted shrubs take 2 to 3 years to establish. They require 40 to 60 litres of water per week. In the first year, water them 1 to 2 times per week and if there are periods of drought of extreme heat then increase to 2 to 3 times a week. Again, like trees much of this depends on the quality of your soil also. During the second to third year water 1 to times a week if there is drought or extreme heat.

Credit: American Home Shield

Sprinklers are great for watering lawns but not good for watering your planting borders as they will encourage shallow root development. In you planting borders you need deep watering to encourage the roots to go down deeper in the soil. This will help to anchor the plants into the ground

Herbaceous Perennials

Newly planted perennials can establish with 1 to 2 years. They require 40ltrs of water per week. During the growing season, water them 1 to 2 times per week and 2 to 3 times per week if there is drought or extreme heat. In their second year, water 1 to 2 times a week during periods of drought or extreme heat.


Like trees hedges have a lot of leaves. It is a wise idea to install a couple of runs of porous hose around your hedge and leave it on a couple of hours twice a week or 3 to 4 hours once a week. Hedges require deep water to get them established.


Trees, shrubs, herbaceous perennials and hedges will all benefit from mulching. Use a fine organic mulch and lay it at a depth of 5cm. This will not only help supress weeds but will prevent water evaporation and feed your soil. Before you lay down the mulch it is a good idea to thoroughly water all your plants. Preparing your soil by mixing good organic matter into it before planting is also beneficial. Remember healthy soil means healthy plants. Mulching does not mean you do not have to water your plants.


Credit: JPR Farm Direct

Use a fine organic mulch in your planting borders. This will not only feed your soil but help with water retention.

Watering Aids

Sprinklers are good for lawns but not good for borders. The water does not penetrate deep enough to help plants to establish. If a plant is only getting water towards the surface of the soil, then that is where its roots will grow. Shallow rooting means a weak plant which will rock in wind and never establish. With Sprinklers water is also not getting to the base of the plant where it is needed and there is also a lot of evaporation. Sprinklers are good for cooling plants on a hot summer’s day.

Porous hoses are a good way to water shrubs and perennials but very hard to calculate how much water is getting to the plants.

The best way to water plants is through an irrigation system with drippers. In a sandy soil the drippers should be spaced approx. 30cm apart and in a clay soil it can be approx. 50cm apart. If you are going to use a hosepipe leave at the base of the plant on a low flow which will allow the water to penetrate deep into the soil. This way there is little wastage and the water is where the plant needs it most.

Newly planted trees could benefit from tree gators used around the base of the trunk. Tree gators are water bags that can be easily fitted around the base of tree and filled with water which slowly drips where the tree needs it most. They are perfect for those people who have busy lives and don’t have time to water their trees.

newly planted trees
Credit: Treegator

Newly planted trees could benefit from a tree gator, especially if you have a busy life. They are easy to install and they will all water to seep through to exactly where the tree needs it.

Watering your plants correctly will help create a deeper root system which means a stronger plant.

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