How Often Do I need to Water my Trees?

Do different trees need different amounts of water?

The short answer to the question: “Do different trees need different amounts of water?” is “yes”. South Florida is home to an assortment of trees in addition to the large and small palm trees which grow between 20ft to 80ft tall respectively. Many of the tree types are not native to South Florida. See which tree names you can identify in your garden.

Large flowering trees:
 Floss Silk, Hong Kong Orchid,  Jacaranda, Magnolia-D.D. Blanchard,  Peltophorum, Queen Crape Myrtle,  Royal Poinciana, Tabebuia – Ipe, Pink Trumpet Tree, Gold Tree, Silver Trumpet Tree, Ylang Ylang.
 Small flowering trees ( less than 20ft):
 Bottlebrush Standard – Red Cluster, Bottlebrush – Weeping, Bougainvillea Standard, Cassia Trees – Desert Cassia, Cassia surattensis and Cassia fistula, Crape Jasmine (AKA Cape or Crepe Jasmine), Crape Myrtle, Frangipani, Geiger, Golden Dewdrop, Hibiscus-Weeping Hibiscus Tree & Hibiscus Standard, Jatropha, Magnolia – Little Gem, Oleander, Parkinsonia, Poinciana – dwarf, Powderpuff, Tibouchina granulosa.
 Accent trees:
 Italian Cypress, False Ashoka.
 Shade trees:
 Black Olive, Live Oak, Mahogany, Ficus, and Gumbo Limbo.

Having identified the trees in your garden, invest some time looking into the type of roots they have. The depth and spread of the roots will build a picture of how to water them.  Some folks believe that the best types of trees to plant are those native to South Florida. Although quite scare and being slow growing, they are energy efficient, low maintenance, and pest and disease resistant. From an ecological point of view, they help to preserve Florida’s natural resources as they are part of the natural resource landscape. The use of native trees though is a bit of a hot potato, amongst the pundits. There is a difference of opinion as to what constitutes “native”, as well as what they contribute to the environment and if they are water friendly. It’s probably best to chat with your landscaper or local nursery if you are interested in native trees. Opinions will probably differ locally. In addition to knowing our tree species, including which are deciduous and which are evergreen, we also need to know our climate.

How often should trees be watered?

In South Florida, trees and gardens require regular and satisfactory drinks of water in summer. It’s important to understand that our soil composition plays a big part. Our soil in South Florida is sandy so it takes a lot of water to saturate it.  After a dry period, the sand acts as a barrier against moisture so rain rolls off it. Consequently, there is a need to water often and long enough to saturate the soil. This means that unless there has been rain, watering is necessary at least twice a week, maybe even three times a week, if rain has been scarce during the hottest months.

In winter, trees and plants don’t grow much at all. The colder temperatures mean that watering only once per week should be enough. Turning the beds over is important though to prevent our sandy soil from becoming too hard for water to penetrate. Using a spiked roller over the areas around your trees to aerate the soil is also a good idea to offset the hardening in the dry months. Turn the beds and use the roller first, before watering. How to water is another important question. Irrigation systems can really help.

Haphazard watering with a handheld hosepipe can waste a lot of water. The lack of efficiency will affect your water bill. Furthermore, if you are not fully focussed on the task at hand, some areas of your garden will end up with more water than others. Over watering can be as harmful to your garden as under watering. Installing an irrigation or sprinkler system is the solution, especially an automated system that is set on a timer and will water areas in a consecutive sequence. An automated system is not only highly efficient, but it also takes the chore out of watering.   Different areas of your garden will require different settings. Short, frequent watering is good for shallow root systems but bad for plants and grass. Similarly, short infrequent watering is also bad. Not enough water, given only sporadically, is quite frankly meaningless to your plants. In order to thrive, trees and plants need frequent, regulated volumes of water in order to grow and flourish. Installing an irrigation system requires a capital layout up front, but should pay for itself through watering efficiently and by saving you money by not having to replace plants that haven’t survived.  An irrigation system will also add to the value of your property should you want to sell it. Ask around to get recommendations for an installer. Have at least three come and chat to you before they give you a quotation.

Is rain enough?

The short answer to the question: “Is rain enough?” is “No.” Rain isn’t guaranteed in the wet season, which is very humid, and there is very little rain during the dry season. These days rain is also not as predictable. The full answer to the question of is rain enough lies partly in understanding not only our tree species, but also in understanding the South Florida climate and annual weather patterns.

It is for good reason that Florida is called the “Sunshine State”. The daily average temperature is 70.7°F (21.5°C) During July temperatures can climb to between 90°F (32.2°C) and 95°F (35°C). On odd occasions temperatures exceed 100°F. The warm ocean plays a role in regulating temperatures, which is why they seldom reach the 100s or, conversely, seldom reach freezing point. Generally speaking, the climate of South Florida is classified as tropical. Some would say monsoon. The summers are hot and humid. The rains come typically in May and carry through to around mid-October. The average annual rainfall is approximately 55″ (1397mm), most of which occurs in the summer and early autumn. Humidity in summer goes up to 75% to 85%.There are some dry spells, often from April to May and in October. Sometimes there is no rain in summer, hence watering is critical.

 Winters are short and usually warm. Winter is normally the drier season, with occasional light rains.  In winter there are dry, windy spells which dry out our sandy soil. Snow is exceptionally rare, but fog is common. Watering is thus definitely required during winter, although to a lesser extent.

Professional Watering Tips

Get water to the roots
A computerised drip irrigation system will help to ensure that water reaches the tree roots without wasting water. If you don’t have such a system, use a soaker hose or a leaky hosepipe. Cover it in mulch as this will to prevent or slow evaporation and will keep the soil moist. This will assist the roots to absorb as much water as possible.

Account for soil conditions
As previously mentioned, the soil in South Florida is sandy and so repels or resists water. This means watering for longer periods at a time.

Prune in winter
Pruning trees helps trees to reduce transpiration in dry times. With fewer branches and leaves to send water to, a tree is able store water for longer periods and so needs to be watered less.

Watering times
Water when temperatures are lower, either in the early morning or late afternoon.
This will give the trees time to absorb water from the soaking soil before the water can evaporate.

Wilting and discoloured leaves will fall off. Outside of autumn, this is an indication that the tree isn’t getting enough water or is being watered at the wrong time of day.

Return on Investment (ROI)

Gardening is a labour of love. Remember that whatever we do in the garden this season will often only give results next season. That’s why it’s important to work towards a bigger picture, rather than taking a piecemeal approach.  When it comes to gardening, the return on investment is not always instant gratification. Investing in an irrigation system will certainly help your “investment” to mature. Planning your garden is equally important. The right trees, in the right place, serving the right purpose (shade or accent, for example)  will achieve your longer term vision and provide the best “return” on your gardening investment which is beauty, tranquillity and a deep sense of satisfaction, all of which is to be enjoyed while watering your trees.