Gardenias and What They Need
Gardenias need acid soil, good drainage, ample water, full sun along coast, part shade inland, and regular fertilizing. If buds fall off it’s not from disease as often supposed, but because plants didn’t get 20 degrees difference between day and night temperatures during spring and early summer. Patios are often too warm at night. Insist on a grafted plant. ‘Aimée’, ‘Belmont’, ‘Mystery’ or cold-tolerant ‘Chuck Hayes’, are good varieties. (Heat-tolerant ‘Kleim’s Hardy’ with single, star-shaped flowers doesn’t need grafting.)
My Gardenia’s leaves are yellowing and I am watering when the top of the soil becomes dry (which is every evening sometimes every other) but they are blooming, I am just afraid the yellowing leaves means that it is unhealthy….HELP!!!
Yellow leaves are a common problem with gardenias. If you live in Southern California you may have noticed the temperature swings we’ve had this year. Abnormally cold weather can cause gardenia leaves to go yellow and fall off. There is nothing you can do about that except next time purchase a grafted variety. Grafted gardenias are only available at the finest nurseries, never at big box stores or discount nurseries. When purchasing a large-flowered gardenia always make sure it’s grafted onto a disease-resistand root stock and you will find all your gardenia problems will disappear. You will also have gardenia shrubs that are perhaps three feet tall and wide and covered in blooms instead of the scrawny little things one often sees in patios. A few yellow leaves my fall from grafted varieties when the temperature is not right but not nearly as many and they grow vigorously and never die from root rot. Next your idea of watering daily makes it sound to me that you are watering too much. Gardenias love moist acid soil and good drainage, but they hate wet feet and this can cause yellow leaves that drop off. Instead of feeling the top of the soil, feel one or two inches deeper. When dry one or two inches down, that’s when to water. Also, morning is a better time to water than evening, since evening watering can lead to disease problems. Thirdly, gardenias love acid soil. Feed at least once a month with Miracid mixed according to package directions. If yellow leaves have green veins, this is due to chlorosis. Treat with chelated iron and trace minerals. If you are keeping this gardenia indoors, that also is a problem. Gardenias belong outdoors so they get a proper spread of 20 degrees between night and day temperatures (which is natural in Southern California in most gardens) This temperature swing is the trick that makes them bloom. Also, they need fresh air, not dry indoors air that makes leaves fall off.