Citrus Trees: an Ideal Indoor
By Sheri Hunter, Colorado Master
GardenerSM, Colorado State University Cooperative Extension, Denver
A citrus tree may be the ideal houseplant for a warm sunny room. Their shiny, dark green
leaves and fragrant blossoms add to the appeal of their brightly colored, ornamental
Citrus trees need fast draining, fertile soil. They require 5-6 hours of sunlight.
Feeding with a high-nitrogen, acid fertilizer should be done in late winter, June and
August. In return for this minimal required care, you will be rewarded with
continuous, year-round fragrant blooms and fruit.
When grown outdoors in favorable conditions, trees grow to 20 feet or higher. Indoors,
they may be kept at four to five feet.
Pests and Diseases
Citrus, as a rule, are bothered by few pests when grown as a houseplant. Yet where
there is a rule, there is an exception.
Protected indoors from normal predators, insect pests can multiply until a plant is
overwhelmed. These pests may include aphids, mites, scale, and mealybugs. This is most
likely to occur if the plant is weak or malnourished. Overwatering, poor container
soil drainage, increased salinity of container soil, and lack of nutrients (nitrogen,zinc
or iron) are conditions that may weaken the plant making it more susceptible to insects
In addition to correcting any existing environmental problems, the following measures
may be needed:
Troubleshooting Indoor Citrus: Pests and Diseases
- If the season permits, and the container is of a size that makes it feasible, consider
moving your plant outside to expose pests to predatory insects.Keep large pots permanently
on a frame with wheels so you can roll trees in and out for spraying and other citrus
- Outside with a garden hose, or indoors in a deep sink or shower, rinse the plant with
insecticidal soap solution. Allow the soap to dry and wait for several days before using
any water rinse. Washing the soap off right away will defeat pest control efforts.
Routinely keep plant free of dust and minor aphid pests by rinsing with a stiff stream of
water. Repeat treatments may be necessary.
- Persistent scale infestations frequently respond to light summer oil spray applied in
spring and fall. Follow directions on the product label and don't spray indoors unless the
product is so labeled and you have adequate ventilation.
- If you resort to chemical pesticide therapy, be sure to pick a product that is
recommended for both the plant and the insect you are treating. Read the label and follow
the directions carefully. Always remember to wash your fruit after using chemicals,
especially if you intend to use the rind.
- If the problem is severe, you may want to compost the plant and start over with
something new. In this case, be sure to clean your indoor space thoroughly, and consider a
period of quarantine.
- Fungal ailments of citrus manifest in yellowing, dropping foliage. Root rot may be
developing related to heavy, waterlogged soil. Reduce your watering frequency. Never allow
the plant to stand in water.
Here are a few suggested citrus trees for the new grower:
|Very hardy; white flowers have pungent sandalwood-like scent; good
|Less dependent on heat for fruit production; Meyers is more disease
||Meyer Improved dwarf
|Hybrid of Mexican lime and
kumquat; shrub-like habit; edible rind
|mandarin needs heat for best flavor
Photograph of dwarf orange tree by Judy Sedbrook.
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