I bought two 5-gallon kumquat trees last year and re-potted them into half-barrels. They had fruit on when I bought them and they fruited nicely through last summer. This year I had some flowers, but not one piece of fruit. I live near the ocean and there was not much sun this summer, do you know why I don’t have any fruit from my kumquats this year?

It sounds like you know the answer to your own question: not enough sun and/or heat.  Much of citrus production, around the globe, including that in California, is done in near desert like condtions.

Still, I would find a fertilizer product specially formulated for citrus.  Often, such products are labeled “for citrus and avocadoes.”

I am also wondering if, living near the ocean, your tree was subject to wind, which could knock off flowers or even tiny fruit.  It is also possible that salt spray from the ocean could have affected your flowers by causing a fungus to grow in them, eliminating the possibility of fruit development.  Finally, citrus are pollinated by bees and other insects.  It might well be that, near the ocean, a lack of insect activity could result in lack of fruit.

Kumquats (Fortunella spp.), based on my observation over the years, appear to be among the most temperamental of citrus trees, at least in our area.  They do not generally look good for more than a decade or so.  This may be because our climate is actually too good for them.  Kumquats are the hardiest citrus species, able to survive 20 degree temperatures just fine.  They actually need a significant dose of winter cold to look their best in spring and summer.  One of the advantages of kumquat trees is their manageable size, as they seldom exceed 10 feet in height.  Fruit, not more than 2 inches long, although somewhat tart, may be eaten whole, together with the peel.

As long as you have a sunny room, you can grow kumquats indoors.  In order to get fruit, you will need to use a small paint brush or Q-tip.  Rub or brush your pollinating utensil over the center of a flower and then apply the yellow pollen that has adhered to it to the center of another flower in order for pollination, followed by fruit deveopment, to occur.

We have a lime tree in our backyard. I’m not sure what kind of lime tree it is. It’s only the second year that we’ve had it. I understand that they don’t get a lot of fruit the first 2 years. There are 7, pretty good-sized, limes on it this year. My question is when do I pick them? My husband thought you’re supposed to pick citrus in the winter, but I noticed the tree is already getting flowers. 

It looks like you have a Bearss lime (Citrus aurantifolia ‘Bearss’), also known as Tahiti or Persian lime.  Fruit gets about as big as a lemon. Immature fruit are green and mature fruit turn pale yellow.   Although most fruit ripens from winter to late spring, some harvestable fruit may be produced throughout the year.  The classic smaller limes known as Mexican or key limes, the type used in bars and for flavoring key lime pie, flourish in the Florida Keys and demand more tropical weather than California provides.

John Bearss developed the lime which carries his name in Porterville, California, in 1895.  Bearss limes are seedless and, although not as acidic as key limes, may be used in just about any recipe that calls for limes.  Their high juice content makes them a fitting substitute for lemons, or lemon juic, as well.

Limes are the most cold sensitive of citrus trees.  Still, they perform well if planted in containers that can be protected from cold in winter months.  Many marginally cold sensitive, containerized plants will prevail on a cold night if they are placed against a wall.  Heat absorbed by the wall during the day will radiate out at night, raising the temperature — by several degrees — around adjacent plants.

I read with interest your column about pomegranate trees,  My husband and I recently moved and inherited a wonderful pomegranate tree. I had never even seen a pomegranate tree before this, let alone own one! About September of last year, it bore some good fruit and then in the winter, of course, lost all the fruit and leaves until this past spring when it just exploded with leaves and fruit. I was very happy until I saw lots of awful bugs on the fruit. I googled them and discovered they are leaf-footed bugs that attack pomegranates. They are horrible and I wanted to get rid of them by using Neem oil. Well, it was impossible to spray the entire tree and all the bugs with Neem oil, so I gave up.

First and foremost, I would make sure that you scrupulously remove all pomegranates from the ground and tree since that’s where leaf-footed bugs are likely to lay eggs for next year’s generation.  Then, in February, I would lay down a 2-3 inch layer of mulch to keep soil moisture level even during the growing season.  This will ensure that your tree’s roots are never stressed and that moisture is taken up by roots and delivered to next year’s growing fruit on a steady basis, which should help prevent fruit split.  If you see baby leaf-footed bugs next year, you should spray them immediately since they are much more difficult to control as they mature.  Neem oil should be effective in this respect.

Neem oil is extracted from the seeds of a tropical tree.  Since it must be consumed, it is effective against insects that chew leaves or suck sap yet is not harmful to bees and other pollinating insects.

Tip of the Week:  Nick Kurek, from Granada Hills, offers this tip to those whose pomegranates, or other tree fruit, are being consumed by birds and/or squirrels:  “My biggest problems with pomegranates are birds and squirrels, who stripped my trees bare a few years ago.  Since then, I’ve been putting lunch bags over the pomegranates with pretty good success.  I twist the bags onto the stems and hold them closed with 2 or 3 layers of masking tape.  Lunch bags are cheap, 40/99¢ at the 99¢ store. As you can see in the photo, some attention is required.  High winds blew off one bag and I am replacing it today.”