April is time to celebrate the outdoors

By Rebecca Jepsen
for the Mercury News
04/05/2008

April is a month packed with great gardening opportunities around the Bay Area and in your back yard. The Spring Garden Market takes place April 12 at Kelley Park's History San Jose. To commemorate Earth Day (April 22), there are many designated walks, as well as restoration and cleanup projects happening all around Santa Clara County.

Arbor Day (April 25) - which took root in Nebraska on April 10, 1872 - was the brainchild of Julius Sterling Morton, a Nebraska journalist who initiated wide-scale planting of trees to improve the Nebraska landscape and economy. Arbor Day is celebrated in many countries around the world as a day for planting and increasing awareness of the importance of trees. It's is a great day to get out and plant a new tree for yourself or with a community project. Some excellent native choices would be California bay laurel, big-leaf maple, madrone or several varieties of oak.

Q: My Satsuma mandarin trees are producing good new growth but have not produced any fruit for the two years that I have had them. Any suggestions?

A: This is a fairly common question. However, the answer can depend on many factors. During the first three to four years after planting, fruit production can be very light. These are called the non-bearing years. Major root growth is occurring and the framework of the tree is being developed.

Sun and water can also affect fruit production. In general, citrus trees need a minimum of six hours per day of direct sunlight. They need to be kept moist, but not soggy. As a rule of thumb, water when the top few inches of soil are dry but the rest of the root zone still feels moist.

Q: I would like to plant a Washington Navel orange tree. Which would be more desirable and faster growing, a dwarf or semi-dwarf? What size container should I plant it in?

A: Dwarf citrus trees generally grow approximately 6 to 8 feet tall; semi-dwarf varieties can range from 8 to 10 feet. Both types will reach maturity at the same rate; larger trees will of course produce more fruit overall. Semi-dwarf trees generally do better planted in the ground. If you want to plant your tree in a container, look for trees grafted onto Flying Dragon rootstock to ensure you are getting a true dwarf. Plant in a five-gallon container or larger, and keep your potting soil evenly moist.