Growing althea in San Antonio is an easy task when you know all the growing requirements you need for success. Our blog today is designed to give you just that.Â
Altheas, a.k.a, Rose of Sharon, are renowned for their stunning flowers, which come in a variety of colors, including white, pink, purple, and blue. The blooms are large, and shaped like small hibiscus, and often attract pollinators like bees and butterflies. The foliage is equally compelling, featuring dark green leaves that provide a lush backdrop for the vibrant blossoms.Â
These deciduous shrubs bloom from early summer into fall, providing the landscape with color during a time when many other bloomers shut down. With numerous varieties available, there’s an Althea to suit every garden style.
Growing Althea: 5 Care Requirements
- Sun Exposure: Altheas need sun for the production of their beautiful blooms, but here in San Antonio, some reprieve from the hottest summer afternoon temps and rays is best. Find a place in your landscape where your plant will receive the majority of the required six hours of direct sunlight in the morning to early afternoon hours.
- Soil Type: These shrubs prefer well-draining soil that is rich in organic matter. A slightly acidic to neutral pH level is ideal for optimal growth.
- Fertilizer Type: Use a balanced, granular fertilizer in late winter or early spring, like a quality slow-release shrub & tree type fertilizer, to encourage lush foliage and abundant flowering throughout the growing season.
- Watering Needs: While Altheas are generally drought-tolerant once established, they benefit from regular watering, especially during dry spells. Ensure the soil remains moist but not waterlogged. You’ll need to pay extra attention during the summertime in San Antonio due to our prevalence for long periods of high heat and drought.
- Plant Protection: Consider mulching around the base to retain moisture and regulate soil temperature. However, avoid piling mulch up against the base or stem of the plant as this could cause rot issues. Mulch will help protect your althea in both the summer and winter seasons. In the event of an unusually cold winter, covering the plants with burlap or frost cloth can help shield them from harsh temperatures.
Growing Althea: Ground vs. Container
While Altheas can grow in containers, we feel they tend to thrive better when planted directly in the ground, where they have more space to expand and receive nutrients and soil moisture from the soil.
At maturity, Altheas can grow to be 8 to 12 feet tall and 6 to 10 feet wide. If you plan to plant them in a container, choose one that is at least 18 to 24 inches in diameter to accommodate their root system and allow for healthy growth.
Growing Althea: Watering Tips for San Antonio:
Dig the hole and plant your althea the same as you would for any tree or shrub. After planting, immediately deep soak the planting area, ensuring the depth of the root ball is saturated. The additional application of a root stimulator product can greatly help reduce transplant shock, as well as jump start the growth and establishment of the plant’s roots.
Altheas will need more water at the beginning of their growth, while they are getting established. But learning to test for soil moisture (to the depth of 6-7 inches) is imperative to figuring out how often you need to reapply water.
Remember, slow, deep, and infrequent waterings are always best for plants rather than fast, shallow, and frequent waterings. The deeper infrequent waterings encourage the plant to send out its roots to look for moisture deep in the soil, resulting in a stronger and more stable root system.
Once established these shrubs can be fairly drought resistant (except during those prolonged periods of both drought and high temps). Signs your althea may need a good soaking are wilting of foliage and leaf drop.
We hope these tips and guidelines for growing this gorgeous bloomer in San Antonio have either helped or inspired you. Remember that at Rainbow Gardens, we are always rooting for your success!
~The Happy Gardener, Lisa Mulroy
Every year my althea gets attacked by aphids. I have been spraying them off with water and then sometimes spraying with insecticidal soap. I have a lot of green anoles living in that bush so I don’t want to use anything harsher. Any other suggestions?
It really sounds like you are doing your best with the spraying off and the insecticidal soap when you want the least toxic approach. Do you abide by any timeline for follow up applications of insecticidal soap and keep to a consistent routine of spraying off? Aphids are rapid reproducers and most pest control attempts are bound to miss a few that then reproduce and start the whole cycle all over again. Make sure you are spraying under the leaves when using the hose method, and also when treating with insecticidal soap. Otherwise….beneficial insects (ladybugs/lacewings) can do the dirty work for you. Looks like we should have a new shipment of these around May 28th at our Bandera location.