Q. We have a mature orange and lemon tree growing next to each other. The lemons are fantastic but the oranges are extremely sour. Our gardener feels that the orange is cross-pollinating with the lemon tree. How can we make the oranges taste better?
A. The rational that lemon and orange co-mingle to produce sour oranges has been used for decades. The reality is it is just a myth. Most citrus are self-pollinating so they don’ require a second variety for cross-pollination, however, there are some exceptions such as the Clementine Mandarin Orange. Most of the pollination is done by Honey Bees looking for nectar or other flying insects. In addition, seedless citrus varieties such as Washington Naval Oranges produce mostly parthenocarpic fruit. Parthenocarpy is the ability of plants to develop fruit without pollination, which means no or very few seeds because the male part of the flower is sterile so no pollen is produce. That being said, if oranges and lemons could mate and this is a very big ‘if’, the maturing fruit would never be affected. The result of the crossing would be in the seeds that then have to be germinated. This is called genetics. Hence this age old answer to sour fruit can’t possibly happen with a maturing crop of oranges. Not every, Bay Area garden is suited for growing oranges. The closer you live to the water the more challenging it is. Sour oranges are caused by not enough summer heat or by harvesting the crop to early. Oranges require six hours of direct sunlight April through October, Naval and Valencia Oranges flower in the spring and turn an orange color in November. Naval Oranges ripen December through March while the Valencia Oranges do not mature until the following June or July. Unlike many other types of fruit, most citrus can be left on the tree without becoming over ripe. If you’re not sure what variety you have, leave the oranges on the tree and taste them periodically throughout the year.
Q. We would like to raise the soil level about one foot around four very old and lovely-blooming Wisterias. Our first choice would be to bury each plant. Is that possible? Our second option is to dig the plants up and replant them. The last thought is to install plant wells around each plant. What would you suggest?
A. Of the three options, the least desirable is to bury the plants by raising the soil level. Actually, this is not advisable at all as it’s a sure way to kill them. The Wisterias could be transplanted to a new location but given their age it may not be feasible. I think the most practical is to build permanent plant wells around each plant. They should extend from the trunk to beyond the drip line. This is where the majority of the roots are located. You can use a variety of materials such as railroad ties, concrete blocks or moss rocks to hold back the soil.
Buzz Bertolero is Executive Vice President of Navlet’s Garden Centers and a California Certified Nursery Professional. His web address is www.dirtgardener.com and you can send questions by email at dirtgarden@aol.com or to 360 Civic Drive Ste. ‘D’, Pleasant Hill, Calif. 94523 and on Facebook Dirtat Facebook/.com/Buzz-Bertolero
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