Tree · Rutaceae
Calamondin Orange
Citrus × microcarpa
A pot-sized citrus that hands you fragrant blooms and sour orange fruit at the same time, all year on a sunny sill.
Full sun
Every 5–10 days
55–86°F · 13–30°C
USDA 10–11
Overview
If you've ever wanted to grow citrus indoors but figured it was too fussy, the calamondin is the one that'll actually go the distance for you. It's a compact little hybrid, usually read as a kumquat crossed with a mandarin, and it earns its spot by flowering and fruiting at the same time. Stick it in a bright window and you'll get fragrant white blooms and small sour oranges together, more or less all year.
Where it's warm, in zones 10 and 11, it'll grow into a small tree outdoors, but most folks keep it in a pot and bring it inside before frost shows up. That portability is really the whole point, isn't it? It also takes hard pruning without a fuss, so you can keep it to whatever size suits your room and still pick fruit.
Just don't expect a sweet orange you can peel and eat. The fruit's really tart, so it's better for marmalade, juice, and a squeeze over your food than for snacking. Give it strong light, even moisture, and a steady citrus feed, and it'll thank you with both the scent and the color.
Care
The short version: give it the brightest light you've got, full sun if you can, keep the soil evenly moist while it's growing and drier in winter, feed it monthly from late winter into fall with a citrus fertilizer, and keep it somewhere warm and out of drafts.
Light
Give a calamondin all the full sun you can, which usually means your brightest window, ideally one that faces south. It'll cope with bright indirect light or partial shade, but here's the catch: thin light means fewer flowers and less fruit.
Water
Keep the soil evenly moist while it's growing, letting the top inch or so dry out between drinks, then ease off in winter. A settled plant can handle a short dry spell, but let it really dry out and you'll lose the fruit.
Soil
Plant it in a rich, well-drained mix, so a loose all-purpose potting blend in a pot, or a sandy to clay loam in the ground. Keep the pH around 6.0 to 7.0 and the roots stay happy while the leaves stay green.
Temperature
It does best from about 55°F to 86°F (13°C to 30°C) and wants nothing to do with frost. Keep it clear of cold drafts and hot vents, since either one can make it drop leaves out of nowhere.
Humidity
Shoot for 40% to 60% humidity, which is easy enough outdoors and in plenty of homes. Dry winter air is what brings on spider mites, so a humidifier or the odd misting really earns its keep once the heating's running.
Feeding
Feed it monthly from about February to October with a balanced citrus fertilizer that has micronutrients. That bit of extra iron, zinc, and manganese is what keeps the new leaves from going yellow on a citrus that likes to eat well.
Pruning
Prune lightly to shape it and to clear out any dead, weak, or crossing wood. Rub off any suckers below the graft union, since they just sap the plant, and trim away as much as you like to keep a potted one compact.
Repotting
Move it into a bigger pot every 2 to 3 years in spring, before the roots start circling inside or poking out the drainage holes. If water rushes straight through or it wilts in no time, that's your sign it's outgrown its pot.
Size & spacing
Left to grow, it gets to 6 to 20 feet (1.8 to 6 m) tall and spreads 6 to 10 feet (1.8 to 3 m), though a pot and regular pruning keep it way smaller. If you plant one in the ground, give it room for that full spread so air can move through the canopy.
Troubleshooting
Most of the time, calamondin trouble shows up on the leaves, and it usually comes down to light, water, or some pest that snuck in. Catch the early signs and you can fix what's wrong before the plant drops its whole canopy. Find what matches yours below, then go from there.
Leaves yellow and drop right after coming inside for winter
Did the leaves start falling the moment the plant came indoors? That's shock leaf drop, and it happens because going from bright outdoor sun to a dim, warm room is a big change all at once. Pop it in your brightest window, keep the warmth steady and away from vents and drafts, and let the soil top dry out before you water again. Bump up the humidity with a humidifier or a quick misting, and you'll see fresh growth once it's comfortable.
Fix:
- Place in the brightest available window (a sunny southern exposure)
- Keep temperatures stable and away from heat vents or cold drafts
- Mist or use a humidifier
- Let soil surface dry before watering
Pale leaves with veins that stay green
When citrus leaves go yellow, it's almost always chlorosis, which just means the plant is either hungry or its roots are too wet. Here's the tell: if new leaves are yellow but the veins stay green, it's short on trace nutrients, and if everything looks evenly pale, it wants more nitrogen. Give it a balanced citrus feed with micronutrients, sort out any soggy drainage, and shift the soil a touch more acidic, which is exactly what it likes.
Fix:
- Apply a balanced citrus fertilizer containing micronutrients
- Improve drainage and avoid waterlogging
- Correct soil pH toward slightly acidic
Sticky leaves, a black sooty film, or fine webbing
Sticky leaves with a black, sooty film? That's the classic sign of scale or mealybugs, little sap-suckers whose sweet honeydew the mold loves to grow on. But if you spot fine webbing and speckled leaves instead, you're looking at spider mites, which really take off in dry indoor air. Wipe the bugs off and treat with horticultural oil or insecticidal soap, raise the humidity to make the mites unwelcome, and keep the plant on its own until it's all cleared up.
Fix:
- Wipe off pests and treat with horticultural oil or insecticidal soap
- Raise humidity to discourage spider mites
- Isolate the plant from other houseplants until controlled
Toxicity
The sour fruit's great to eat, but the rest of the plant isn't really pet friendly. The leaves, peel, and fruit carry essential oils and psoralens that can upset an animal's stomach and make skin touchy in sunlight. Keep pets and livestock away from the foliage and prunings, and wash your hands once you've handled it.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
If a cat has a nibble of the leaves or peel, you might see drooling, vomiting, or loose stools, and it'll often go quiet and skip meals for a bit. The oils can make its skin touchy in sunlight too, so keep that in mind.
Dogs Mild
A dog that chews the foliage or fruit usually ends up with an upset stomach, so think vomiting or diarrhea plus a bit less pep than usual. Those citrus oils can also leave the skin prone to a sun rash.
Horses Mild
The oils and psoralens in the leaves and peel don't sit well with a horse's gut and can leave it dull and out of sorts. It's worth clearing clippings and any dropped fruit out of the paddock.
Rabbits Caution
Those same irritant citrus oils make the leaves and peel a bad call for rabbits, so the safest bet is to keep them well clear of the plant.
Livestock Caution
Goats, sheep, and cattle will probably react to the foliage oils just like other animals do, so fence the plant off and bin the prunings instead of leaving them within reach.
Birds Caution
It's best to treat the essential oils in the leaves and peel as off limits for pet birds, even though a thin sliver of the ripe flesh gets offered now and then.
People Fruit safe
Here's the upside: the sour ripe fruit is a kitchen favorite and totally safe for people to eat. Just wash your hands after pruning, since the oils in the leaves and peel can irritate skin and make it touchy in the sun.
Leaves, peel, and fruit contain irritant citrus oils; wash hands after pruning or handling fruit and keep fallen leaves and peels away from pets.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
There are only a couple of forms you'll run into at home or the garden center, and they mostly come down to how the leaves look.
Variegata (variegated calamondin)
You'll spot it by the leaves streaked green and creamy white, plus young fruit that shows green-and-white stripes which fade away once it ripens.
Standard calamondin
This is the plain glossy-green one, and it's what most people grow as an ornamental indoor citrus.
How to propagate
You've got a few ways to grow more calamondins at home, from cuttings to seed, though the quickest and most reliable plants usually come grafted from a nursery.
Stem cuttingsModerate
Late spring to summer · About 6 to 10 weeks to root
Want to try cuttings? Take them in late spring or summer, dip the cut ends in rooting hormone, and keep them warm and humid under cover. Do that and they'll root in about 6 to 10 weeks into plants that match the parent exactly.
SeedModerate
Spring · Several weeks to germinate; years to bear fruit
Sow fresh seed in spring and it'll sprout within a few weeks. The handy thing is that calamondin seeds are often polyembryonic, so the seedlings come fairly true to type, but they're slow growers and it takes years before they fruit.
GraftingDemanding
Spring to summer · Several weeks for the union to take
Most nursery plants come grafted in spring or summer onto a vigorous rootstock, and the union knits together over several weeks. It's the trickiest one to manage at home, but it does pay off with faster growth and earlier fruit.
Myths
Calamondin fruit is poisonous to people.
Nope, the fruit's very sour but completely edible, and cooks turn it into marmalade, juice, and a sharp seasoning. It's acidic, not poisonous, so there's nothing to worry about. The real watch-out is for pets, since the oils in the leaves and peel can irritate them.
Calamondin is a true orange species.
The name's a bit of a fib, because it's actually a hybrid, Citrus x microcarpa, usually read as a kumquat crossed with a mandarin. It isn't a true orange, and that mixed-up parentage is a big part of why the fruit tastes so tart.