A few weeks ago, I gave our citrus bushes their first application of fertilizer for the season. I have read repeatedly how important it is to fertilize citrus with nitrogen especially in late winter to stimule them to grow and bloom in the spring. I have been using a 16-16-16 all-purpose chemical fertilizer on our citrus. We have two mature orange bushes (below picture), a very small page mandarin bush, and a small navel orange bush (picture above). A week after I applied the fertilizer, the mandarin and the small navel orange bush dropped many of their still green leaves. The picture above show the small navel orange after the leaf drop occurred.

I gave the small orange and mandarin about a cup of fertilizer each, which was probably too much. We had only a few light rain showers in the weeks after I fertilized, and I did not give them supplemental watering. Also, the weather has been cool with many cloudy days in the past few weeks, but we have not had any freezing weather. So I can rule out overwatering and weather conditions as possible causes. Last spring, our small orange lost even more of its leaves within a few weeks after I applied the same fertilizer.

Although leaf drop on citrus can occur for a variety of reasons, I am convinced at this point that the leaf drop has been occurring, because I have been applying too much fertilizer, which burned the roots. I have decided to start using an organic fertilizer on our citrus bushes and to use much less fertilizer, perhaps a third of a cup per application on our small bushes. I have read that organic fertilizer is less likely to burn the roots than chemical fertilizers, because the nutrients in them are much less concentrated. Our mandarin seemed to suffer the most after I gave it fertilizer. That’s strange because it had many yellowing leaves that were a clear sign of nitrogen deficiency. However, it is a very small bush (only about 18″ high), so it was probably more susceptible to root burn.

Our large mature orange bushes did not mind the chemical fertilizer. I gave them about 3-4 cups of fertilizer each. They lost very few leaves after I applied the fertilizer, which seems to confirm what I have been reading that mature trees can handle large doses of fertilizer much better than young trees. In the past few years after giving our 2 large orange bushes a few cups of all-purpose fertilizer in February, they responded by producing an abundance of blossoms and new dark green leaves the following spring.

The house we live in came with mature valencia and navel orange bushes. The navel oranges ripen in the spring. The valencia oranges ripen in the summer, right in the middle of the fruit season for so many other plants we have growing in our yard. Because we are so busy eating other fruits, we often leave many of our valencia oranges on the bush for months after they are ready to pick. Valencia oranges can hang on the branches for months after they are ripe without losing quality or rotting. Sometimes I leave some of the fruit on the bush until October early November.

Our valencia bush typically produces over 100 fruits each year. This year it has about 200 oranges. They are good for eating fresh, although they are not as tasty and sweet as the navel oranges. We use most of our valencias to make fresh squeezed orange juice, which is so good. I usually add a teaspoon or two of sugar to each glass to make it extra sweet. I squeezed about 8 oranges to make the two glasses in the bottom picture.

Oranges are tricky plants to get established. In order to get oranges to thrive, they need lots of nitrogen rich fertilizer, applied in the late winter and spring. And in my opinion, they also need regular watering.

I have planted several oranges, because I wanted to try new varieties, and because I wanted another navel. Most of the young oranges I planted have died. Several of the young oranges I planted died as soon as their root balls dried out in the summer. The mature oranges we have are better able to tolerate dry periods than the recently planted oranges. My theory on oranges is to keep them well-fed and well-watered, just not saturated or water logged. I have read many posts on other sites claiming that oranges like to dry out between waterings. That technique has never worked for me.

We are lucky enough to live in a house that has an established navel orange bush (see picture). It was planted by one of the previous owners. This bush must be over 20 years old given the girth of its trunk.

Our navel orange bush produces the best tasting oranges I have ever eaten. The flesh of the oranges is soft and tender, unlike the tough fleshed oranges I typically buy in the supermarket. And the flavor is superb. They are juicy, with a nice sweet-tart orange flavor. Although I cannot be sure what type of navel it is, I believe it is a Washington navel given the high quality of the fruit. Washington (Bahia) navel is generally considered to be the best tasting orange.

Although navel oranges are known for ripening in the winter, our navel oranges are ripe now, in April and May. Our climate is probably too cool to stimulate winter ripening, but it appears to be warm enough to generate some very good fruit. Our summer highs average in the high 70s to low 80s, and our winter highs average in the 50s.

The first two years I lived in this house, the leaves of this bush would turn yellow each spring. Then, I learned that yellowing leaves is typically a sign of a lack of nitrogen. Oranges need lots of nitrogen, particularly in the spring when they are growing and blooming. For the past several years, I have been fertilizing our two oranges (navel and valencia) once a month from February through July with a general purpose fertilizer, 16-16-16. The first of these three numbers indicates the percentage of nitrogen in the fertilizer.

I give each bush 3-4 cups in each application, because both of them are quite mature at this point. The result has been more blooms, more oranges, and beautiful dark green leaves throughout the spring and summer months.

Some of our neighbors have large orange trees. They never seem to fertilize them and yet they always look beautiful! I am not sure how they get away with neglecting these trees. Although, our bushes often have more oranges even though they are smaller.

This photo is a picture of a Valencia orange tree growing in our yard. I am still harvesting oranges from this tree in late September. Valencia oranges typically ripen in mid-summer in our area. Yet, unlike many other types of fruits, Valencia oranges do not need to be picked soon after they ripen. I am amazed at how well Valencia oranges maintain their quality, even after remaining on the tree for months after ripening. Because they last on the tree so long, we can focus on eating fruit from our peach and pear trees in August, while we save the oranges for a later harvest.

Valencia oranges are tasty and juicy fruits. We often use them to make fresh orange juice. Some of them are great for fresh eating as well. Although, I have found that our Valencia oranges are generally not as consistently good for fresh eating as the oranges from our navel orange bush. The navel oranges are nearly always tasty, sweet, and tender. On the other hand, my experience has been that Valencia oranges are easier to grow than navels. Valencias don’t seem to require as much care as navels.