Orange trees. You might think they’re only for places like California and Florida. We’re glad to say that’s not so!
Oranges can be planted in-ground in zones 8-11 and grown in containers in zones 4-7. This means nearly anyone in the US can grow an orange tree. But there are things you need to know for your tree to successfully produce oranges.
Keep reading to learn about orange tree pollination – how it happens naturally, what you can do to help it along, and what to do if manual intervention is necessary.
Do Oranges Need Pollination Partners?
It all depends on the orange variety you want to grow. Oranges fall into two categories:
- Self-fertile, or self-pollinating oranges that don’t require another orange tree in order to set fruit.
- Non-self-fertile, or non-self-pollinating oranges that won’t set fruit unless there’s an orange tree of a different variety planted nearby.
That’s not all there is to know about orange tree pollination – it goes a level deeper.
Two Types of Pollination
Self-pollinating oranges trees can be broken into two categories, depending on the form of pollination that occurs.
There are oranges that self-pollinate sexually when pollen is moved within the flower by natural means.
Parthenocarpic oranges pollinate asexually and the fruit forms without pollen. This is referred to as “virgin fruit set” and it results in seedless fruit. Interestingly, it’s been shown that parthenocarpic oranges produce more fruit when there’s another orange nearby to pollinate.
Sexual pollination oranges
Here are some popular orange varieties that pollinate sexually, broken down into self-fertile and non-self-fertile categories.
- Valencia Orange
- Blood Orange
- Honeybell Orange Tangelo hybrid
- Arizona Sweets
- Ambersweet (tangelo-mandarin)
- Honeybell Orange trees need compatible orange varieties for cross-pollination.
- Fairchild (mandarin) cross-pollinates with Temple, Clementine, Kinnow, or Orlando
- Minneola (tangelo) can be cross-pollinated by Temple, Dancy, Kinnow, Orlando, Seminole oranges, Satsumas, or any kind of mandarin.
- Orlando (tangelo) can be cross-pollinated by Clementine/Algerian.
Here are two popular parthenocarpic orange varieties.
- Clementine (mandarin)
How Pollination Affects Fruit
The varieties of oranges that are planted near your orange tree will have an effect on the fruit, specifically the fruit’s seeds.
Some oranges produce seedless or nearly seedless fruit when nearby varieties are the same. But when the varieties are different, the fruit has seeds.
Those seeds carry the DNA from the fruit-producing tree and the nearby pollination partner. So if you try to grow orange trees from seeds of a fruit that was cross-pollinated, you can’t predict which tree the seedling will take after.
The taste of an orange, on the other hand, is not affected by a pollination partner. A fruit’s taste always comes from the tree the fruit forms on, not the other tree that pollen came from. This is known as fruit being “true to type.”
How Do Oranges Pollinate Naturally?
A fun fact about orange tree pollination is that trees pollinated by bees produce 35% more oranges than trees not pollinated by bees. This means that bees are, by far, the best pollinators for orange trees. Specifically honeybees, leafcutter bees, and sweat bees.
Wind also carries pollen from orange blossom to orange blossom, as well as from orange tree to orange tree.
Hummingbirds enjoy visiting orange trees and you’ll enjoy watching their antics during their visits.
Other insects that assist with orange tree pollination include butterflies and flower flies, which look similar to bees but have fewer pairs of wings.
Other Things to Know About Orange Tree Pollination
Pollination occurs when flowers are blooming, usually in mid-spring. Buds begin forming in early winter, so you’ll want to monitor for reports of freezes or adverse weather conditions that could damage the tree’s flower buds.
Once they bloom, 99% of orange blossoms fall off without producing any fruit.
Pollen amounts in each orange blossom are so small that a honeybee has to visit 10-15 blossoms just to gather up enough pollen for pollination to occur. Pollinating orange trees is hard work for bees!
When is Manual Orange Tree Pollination Necessary?
There are a few specific cases where you’ll need to lend a hand with orange tree pollination.
Greenhouse or Indoor Trees
You’ll need to manually pollinate if you grow oranges In greenhouses or as indoor container trees. Bees aren’t going to be able to get to the blossoms on your tree, which means you have to do their job.
Cool Blooming Season
Manual pollination also has to be done during unusually cool weather during the blooming season.
Insect Labor Shortage
If your area is experiencing a low pollinator insect population, then it’s up to you to fill in and do the job of pollinating your orange tree.
Lastly, you can manually pollinate orange trees if you want more fruit from your tree. You already know that when left to nature, only 1% of the flowers produce fruit. The more effort you put into getting each and every blossom pollinated means more chances for a higher fruit yield.
When, Exactly, Do You Manually Pollinate Orange Trees?
Knowing the conditions that call for manual orange tree pollination isn’t enough. You have to know when the blossoms themselves are ready to be manually pollinated. This means you need to get up close and personal with your tree’s flowers.
When you examine an orange blossom, look for two things.
- Some loose, yellow pollen grains.
- The anthers look “shiny” and “wet.”
When you see these two signs, it’s go time!
How to Manually Pollinate Orange Trees
Manually pollinating orange trees is done via the same technique used for other fruit trees.
You need a soft tool such as a camel hair artist’s paintbrush or even a soft makeup brush. In a pinch, small cotton balls will work.
Gently blot a blossom to gather pollen onto the brush hairs or cotton ball. Then move to the next blossom and repeat the process.
Keep gathering pollen and moving along. The idea is to move pollen from one flower to another and not simply move the pollen around inside the same flower.
Repeat this once a week until there are no more blossoms on your orange tree in order to create the highest yields.
For obvious reasons, this isn’t something you want to do for a grove of orange trees or if your orange tree has grown quite large. Manual pollination is best for orange trees that are manageable in size (containers or dwarf varieties).
How do I know if my orange tree pollination efforts have paid off?
Again, you’ll need to get up close and personal with the blossoms to look for the signs. When the flower petals fall off and you see a tiny green fruit down inside the column the stigma sits on, successful pollination has occurred.
Your fruit is on the way!
Best Practices for Natural Pollination
While it might seem like orange tree pollination is out of your hands and completely up to the whims of nature, there are some things you can do to increase the chance of pollination happening.
Nature’s Little Helpers
Hands down, the best thing you can do for your orange tree is to encourage bees to come to pollinate it. In fact, entice as many animal kingdom pollinators as you can – can any garden have too many hummingbirds or butterflies?
Use Sprays Conservatively
Read the labels of all pesticides/insecticides to make sure using them won’t harm or deter bees or other pollinator insects. Ideally, delay spraying until after the blooming season has ended.
If you’re planting new orange trees, space standard-sized trees 15-20 feet apart. Dwarf varieties should be planted 8-12 feet apart.
Do Your Homework and Know Your Tree
Make certain you’ve selected the right pollination partner for any non-self-fertile orange tree you’re planting.
Watch For Inclement Weather
Protect the blossoms that will eventually become fruit!
Move container-grown oranges inside for the winter. For in-ground trees, protect the flower buds from freezes or other weather that may damage them by covering them with fabric. Just make sure it’s not heavy enough to do any damage to the tree.
If cold weather (below 27 degrees) will be in the area for a while, you can also wrap Christmas lights around your tree. After covering them, plug the lights in to create additional warmth against the cold.
How Long Until There Are Oranges?
You’ve done the (hard) work of manual orange tree pollination and you’ve seen the tiny green promises of future fruit. It makes sense that now you’re wondering how long you have to wait until you can savor homegrown oranges.
The answer is anywhere from five to 18 months. It all depends on what variety you’re growing.
In comparison, navel oranges need seven to twelve months to ripen, whereas Valencia oranges aren’t ready for harvesting until 18 months after the fruit set. This is why you’ll often see flowers and fruit at the same time on a Valencia!
If you have a backyard orange tree and you’re worried about having too much fruit to harvest at the same time, there’s good news. Oranges can be left on the tree for long periods after maturing (sometimes up to four months) without overripening. Even better – the longer they stay on the tree, the sweeter they get.
This means you don’t have to rush to harvest all the fruit at once.
Ideal Conditions for Orange Tree Pollination
The best orange tree pollination happens when the natural conditions are right – when bees and wind can do the hard work. There are things you can do to help by following the best practices in this post.
But if the situation calls for you to step in and take on the job of pollinating an orange tree, you’ll know what to do!
Excited for more orange content? Check out our orange trees page to start learning everything there is to know about your favorite citrus!