Oleanders are beautiful tree-like shrubs that thrive in USDA growing zones 9-11. These plants have leathery green leaves and flower in an assortment of beautiful colors.
If you want to add oleanders to your yard, one of the biggest misconceptions about these plants is their watering requirements. Some people say that once a plant is established you don’t need to water at all, and others say to water often.
The key to learning how to water oleanders is to learn about oleander overwatering symptoms and how these impact the growth and overall health of the plant. The key symptoms include yellow leaves, leggy growth and unpleasant smell.
Watering your Oleander
Oleanders can reach heights of up to 20 feet tall when given optimal care. So what does optimal care look like? Oleanders prefer to be planted in well-draining soil and thrive in the sandy soils of the southern United States.
These plants like to be watered regularly during the growing season. I usually start out at twice a week with my plants and adjust based on how they do. You will want to let the soil mostly dry out between waterings or you run the risk of overwatering your plant and causing root rot.
If your oleander has developed yellow leaves, it is likely due to either overwatering or underwatering. Check your plant’s soil. If it is soggy and wet you are likely overwatering, if it is bone dry you are underwatering.
If your soil is overly soggy, you will want to check its roots for rot. Remove your plant from the soil and rinse the roots. Healthy roots will be firm and white, rotting roots will be dark brown or black and mushy. Remove any rotten roots and replant your oleander in fresh soil.
If you are keeping your plant in a pot, you will want to select one that has a drainage hole and is the appropriate size. It can be tempting to get an overly large pot for your plant since you know it is eventually going to get quite large, but placing a small plant in a large pot can lead to water stagnation, root rot, mold, and fungus.
Oleanders will also sometimes develop yellow leaves near the bottom of the plant as they age. This is completely normal and a part of their growth cycle.
These leaves will eventually turn brown and fall off, as long as you have a good watering schedule and your soil looks healthy. This is nothing to worry about.
Plants that are overwatered will also sometimes exhibit tall leggy growth. In an effort to get more sunlight and absorb more water, they will put all their energy into more growth and reaching more sunlight.
While this may sound good, if your plant isn’t spending a balanced amount of energy on both root and foliage growth, it will end up with more leaves than its roots can support.
It is easy to overwater plants that aren’t receiving enough sunlight. Oleanders prefer to be planted in or kept in direct sunlight. If you are keeping your plant inside, a south-facing window would be an ideal place to keep it.
However, if you don’t have a south-facing window, placing it in a bright window with supplemental light from a plant grow bulb can work just as well. Plants absorb water during photosynthesis, so if your plant isn’t getting enough sun they won’t photosynthesize properly and won’t absorb enough water from the soil.
Soggy soil can also lead to mold and fungus developing. While you may not notice this as much outside, but if your plant is indoors it will exhibit an unpleasant odor. It may also attract small bugs called fungus gnats. Pulling your plant from its pot and replanting in fresh soil is the best way to solve fungus or moldy soil issues, but it might not completely take care of the gnats.
To rid yourself of the gnats, many people use a product called a mosquito dunk. Dissolve these according to the instructions into your watering can once per week and use it to water your plant.
After about a month of this, your gnat problem should be solved. If you want some extra protection though, you can also put sticky fly traps near the soil of your plant to trap any mites that may be hanging around.
Creating a Watering Schedule
A good watering schedule encourages your plant to extend its roots throughout the soil or the pot and produce healthy lush foliage. Watering your plants regularly also trains the plant that it can grow healthily instead of worrying about when or if it will be getting water.
Most oleanders prefer to be watered every 3-4 days. If your plant is outside, you can water with a hose for a few minutes. If it is inside, you can water until you see drainage from the bottom of the pot.
Check your soil in 3 days. If the water has all been absorbed and your soil is dry, you are ready to water again. If it is still wet, give it another day or two and check again. If it is still wet after 5 days, you may be using the wrong soil or your plant may not be getting enough sunlight.
Once you know your plant’s ideal watering frequency, you can keep your plant healthy, happy, and thriving!
Most of the advice in this article is geared toward caring for your plant during the growing season from spring to fall. If you are in grow zones 9-11, your plant can stay outside during the winter, but if you are in other zones you may want to bring your oleander outside.
Oleanders can tolerate temperatures down to about 20 degrees, but they will sustain some damage at this temperature and will need to be heavily pruned in the spring. You can forgo watering once temperatures drop below 50 as your plant will be dormant. If your plant is inside, you may still water as needed, but much less frequently than in spring-fall.