Well, according to Dr. Ed Gilman, UF/IFAS environmental horticulture professor, not as much as you think.
This is good news for your utility bills and the environment. A new University of Florida research study shows that landscape shrubs need much less water to establish healthy roots than you might expect.
North of Orlando, Gilman recommends using as little as 1 gallon of water per shrub applied every eight days. In South Florida, he recommends every four days. In the first year after planting, water 1 to 2 gallons of water when there is less than a quarter inch of rain within a two week period.
Gardeners should maintain their irrigation schedule until shrubs can survive on rainfall alone, once roots have grown to the edge of the plant canopy, which is usually about 28 weeks.
Several simple steps can help ensure your plants survive establishment:
- Consider planting at the start of the rainy season.
- Irrigate based on location, weather and desired plant vigor.
- Apply water directly to the rootball.
- Use low-volume irrigation. Don’t irrigate if a quarter-inch or more rain fell in the last 24 hours.
- After establishment, irrigate when there are signs of wilting, but before leaves begin to die.