Key Lime Tree Plants

You'll notice that many grocers label key limes as "Mexican limes" or "West Indian limes." Most key limes available at the grocery are grown in the southern United States, Mexico, Central America, or South America. That's because key lime trees flourish in warm climates! However, this dwarf version of the Citrus aurantifolia is known for its short stature and hardiness. No matter where you live, you can make this key lime tree work — especially if you're willing to plant it in a container and welcome it into your home. In hardiness zones 9 and 10, our key lime tree will thrive — and flower! — all year long. For all zones north of 9, try planting these beautiful trees in containers and overwintering them indoors.

Key lime trees have thorns, as do nearly all citrus trees! Lemon, lime, orange, and other citrus trees have evolved with thorns to protect themselves from wildlife. Hungry animals love to nibble on those tender leaves and flowers! Although some key lime varieties have been bred to be thornless, those varieties typically don't share the same sweet fruit of the classic Mexican Key Lime.

Your new key lime tree will have large thorns. You may notice that the tree "outgrows" its thorniness: as it grows bigger, stronger branches, the rate of thorn growth won't match the rate of tree growth. That's because thicker branches don't need as much protection as young shoots. If you'd like to make the tree look a bit friendlier, you can trim thorns at the nodes: just don't cut into the green of the branches. You'll want to wear gloves while harvesting your key limes.

Key limes are more tart and less acidic than traditional limes, such as standard Tahiti or Bearrs Persian limes. This variety of key lime plant is a bushy, glossy-leaved beauty that serves as both an ornamental and fruit-bearing tree; traditional lime trees are taller and woodier. The fruit of the key lime tree are also smaller and rounder than Persian limes, and they have a yellow-green color.

Many chefs think of key limes as a dessert-only lime. So, are key limes sweeter than regular limes? They are, but they also pack a pucker! These limes are sweeter and more sour than Persian limes, and they also have a light floral flavor. Their lack of acidic taste makes key limes the perfect cooking lime. And, their intense sour-sweet flavor makes key limes excellent for cocktails, marinades, limeades, syrups, and, of course, key lime pie.

Key limes have long been associated with the residents of Florida, California, Mexico and Central America — but, with dwarf cultivars like Spring Hill's, you can grow a key lime tree in a container indoors. Or, move your tree outdoors during the summer, and bring it indoors during winter!

These dwarf key lime trees grow from 4 feet to 6 feet tall, making them perfect for a large container. While you don't need to prune your key lime tree unless its branches interfere with one another, you can trim it to maintain a size smaller than its maximum height of 6ft. If you're growing a key lime in a container, make sure it's well-watered — containers don't hold as much moisture as outdoor soil — but not soggy. Make sure to bring the tree indoors before the first frost.

During the summer, place the container outside and in a spot protected from wind: key limes have shallow root systems and can blow over in storms. In order to produce fruit, your key lime tree does require pollination: if it's outdoors during the warmer months, bees and breezes take care of the pollination for you. If you keep your key lime tree indoors year round, you will need to hand-pollinate the tree with a small paintbrush.

Lime trees self-pollinate, since their flowers contain both male and female parts, so they provide their own pollen. You do not need a "male tree" and "female tree" to produce fruit — you only need one key lime tree to harvest limes. If you grow a lime tree outdoors, or move your lime tree outdoors during the summer, bees and other pollinating insects will pollinate the tree for you. If you keep your tree indoors year round, you'll have to transfer the pollen by hand.

The center of the lime flower includes the stigma, the sticky female part of the flower that accepts pollen. Long filaments called anthers, which hold fluffy yellow pollen on their tips, make up the male parts of the tree. In order to pollinate key limes indoors, you can use a small paintbrush or cotton swab to transfer pollen from the male anthers to the female stigma of each flower you want to grow fruit. Be gentle, and be sure not to damage the flower, while making sure that some of the pollen sticks to each stigma.

Coffee grounds, and the acidity and nitrogen they produce, can help your key lime tree flourish! Coffee grounds attract worms, deter slugs and snails, and slowly release nitrogen into the soil as they break down. They're also slightly acidic, which makes them a good fertilizer for acid-loving citrus plants. Don't throw raw coffee onto your plant, though, as straight coffee grounds can make the soil too acidic. Instead, amend your soil with coffee grounds, and test your soil pH: it shouldn't go below 5 to 6.

Regular lime juice can be used in the place of key lime juice — but the results aren't as sweet. Just try a key lime pie from the freezer section of any supermarket: these pies are often made with the concentrated juice of Persian limes, not keys. The difference in flavor will be subtle, but regular lime juice produces a more acidic, "bitey" after-taste. However, some chefs happily substitute lime juice for key lime juice (keeping in mind that key limes are about half the size of other limes). Some cooks use key lime juice for rice dishes, and chicken marinades, in place of traditional limes — and find that the sweeter taste is a pleasant surprise!