Monday, February 29, 2016

In Love with Mandarin Oranges

Do you love fresh mandarin oranges? I do. When we moved into our house in Rockport, Texas, I was thrilled to find two huge citrus trees in the yard. One was obviously grapefruit, but it took about six months to figure out that the tree with little green balls on it was a Changsha mandarin. Some people call them Changsha tangerines, and with the help of Ginger Easton Smith, our local Agriculture Extension agent, I came to understand that the terms “tangerine” and “mandarin” are often confused. The tangerines make up a subset of the mandarins, but some people use the terms interchangeably. Clear as mud, right?

The Latin name for this orange tree is Citrus reticulata ‘Changsha.’ People call it a Changsha mandarin or a Changsha tangerine or just a Changsha—my personal preference.  It’s one of the most cold-hardy of the citrus varieties, and the trees grow in a more upright arrangement than most other types of citrus.  The fruit is nice and sweet, easy to peel, medium-sized, and it has a flat bottom, slight vertical indentations like a pumpkin, and lots of seeds.  Lots.


If you want to propagate a Changsha, starting from seed will give you a more cold-hardy tree.  In addition, Changsha is one of the few orange varieties that serve as root stock for grafting other citrus onto.  A more widely used variety of root stock, trifoliate orange, is less cold-hardy and it produces inedible sour oranges on its own.  In addition, trifoliate orange is an invasive species in Texas--not a good idea to plant it.  Changsha, in my opinion, doesn’t actually need any grafting—the fruit is delicious and abundant.  And the trees actually grow better than trifoliate orange in a variety of well-drained soils, like alkaline and even saline.

It’s hard to grow citrus from seed, but there’s a shortcut that makes it easy: peel the seeds. As soon as you get a plump, undamaged, mature seed out of the fruit, rinse it off to prevent mold growth in the coming days. Then carefully use a sharp knife to make a tiny slit in the pointy end of the seed covering. Don’t cut into the actual seed inside. Then starting at the slit, peel the covering away and place the seed in a plastic bag with a folded damp paper towel. Use good non-chlorinated, non-salty water on the paper towel. Seal the bag and keep it in a warm spot. It doesn’t need light, so on top of the ‘fridge is fine. Go ahead and put several peeled seeds in the bag, because not all of them will germinate. Check the bag every day. If you see mold on the paper towel, replace it. Watch for a little root growing out of the seeds. Some can germinate in a couple of days, but don’t give up on the others. It can take a few weeks sometimes.

When a seed has germinated, plant it in a small pot of vermiculite, and wet it well with good-quality water. Keep the pot in a warm place until the seed sprouts up above the growing medium. Then move it to a warm, sunny spot. Keep it damp, but don’t over-water. Stick your finger in the medium to see if it’s dry, and then add water until it runs out of the holes.

After a couple of good, green leaves have unfurled, transplant the seedling into a larger container with a more fertile medium to grow in.You can use a mix of vermiculite, peat moss, and compost like the square-foot gardeners. Just be sure that it drains well.


Mandarin orange trees can be planted outdoors on the southern side of your house for protection from cold. They can also be grown indoors in pots, as long as you have a very sunny window. They generally start producing fruit in just a few years, sooner than larger citrus fruits. New trees will need water in the form of rain or irrigation once a week. After they’re established, every two weeks is fine. You can fertilize them by spreading compost or worm castings two or three times a year: late winter before blooming, late spring, and again in early fall if you want.


Leave the fruit on the tree as long as you can during the winter. This causes it to sweeten up quite a bit, especially in cold weather. But the fruit can be damaged by a hard freeze, so when one is forecast, pick them all the day before. Mandarin peel is delicate. Don’t pull the fruit off the tree—cut the stem so you won’t tear the peel. Your harvested oranges will last much longer that way.

Helpful Links

To find out what happened to our tree in Hurricane Harvey, see:
Life Goes on Like Gangbusters: An Orange Tree Story

This post is part of Orange Week on the blog.  Check out the other posts:
Avocado & Orange Salad
Orangey Jar Cozy
Victoriana at Its Best