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What's Hot Archive 2016

What's Hot in January

frost blanket
by Brent McGhie

How can I protect my citrus trees from frost damage?

Citrus trees benefit from being planted in a sheltered area. Healthy, well-irrigated trees are better able to endure freezing temperatures.  Keep the ground around citrus trees bare because bare, moist soil is better able to absorb and reradiate heat than soil covered by mulch or other ground covers. Young trees (one to three years old) can also be covered entirely, using a light material to trap heat being radiated by the ground. A frame or stakes should be used to minimize contact between the cover and leaves because ice may form where the cover touches any leaves. Sheets, burlap, or tarps are a better choice of cover material than plastic because plastic transfers more heat and if leaves come in contact with it they are more likely to freeze.  The cover should extend as close to the ground as possible and be removed the next morning after the temperature rises. 

For more information see:
Frost Protection for Citrus and Other Subtropicals
Avoiding Cold Damage to Citrus (pdf)

What's Hot in February

bulb planting chart
by Brent McGhie

When should summer-blooming bulbs be planted?

February is a good time to plant summer-blooming bulbs, including amaryllis, calla lily, cana lily, dahlia, gladiolus, lily, and tuberous begonia. February is normally the last month to sow seeds of spring-blooming native annuals as well.

For more information see:
Bulb Planting Schedule (pdf)

What's Hot in March

by Brent McGhie

When should citrus trees be fertilized?

Citrus trees are heavy feeders, and they can benefit from feeding with an organic or synthetic fertilizer formulated specifically for citrus. Read and follow the label directions for how much to feed your trees and apply the fertilizer three times during the growing season. Feed in March before bloom, again in May, and make the third application in June. An annual application of compost is also beneficial to citrus and may provide sufficient fertilization.

For more information see the Master Gardener Planting Guides:
Growing Citrus in Sacramento (pdf)
Fertilization Citrus 

What's Hot in April

thinning immature fruit
by Brent McGhie

When is the best time to thin fruit on peaches, plums and nectarines?

Thinning is done to prevent branch breakage and get larger fruit. The best time to thin peaches, plums and nectarines is when the fruit is about ¾” in diameter. Fruit usually reaches this size from April to mid-May. Peaches and nectarines should be thinned to 5" - 7" apart on the branch, while plums and pluots should be spaced about 4" – 6" apart.

For more information see:
Thinning Young Fruit
Fruit Thinning 

What's Hot in May

by Brent McGhie

How can I control earwigs without using pesticides?

To control earwigs place rolled newspaper, corrugated cardboard, or pieces of garden hose in the garden. Earwigs will take shelter in these objects and can then be shaken into a bucket of soapy water.

For more information see: Earwigs 

What's Hot in June

by Brent McGhie

How do I get rid of tomato hornworms without using pesticides?

The most common method of controlling hornworms is hand picking or snipping them with shears. If this method is distasteful to you, or the infestation is out of control, an organic spray of Bacillus thuringiensis, or Spinosad may be applied. This spray is safe for pets and wildlife. Disking the soil after harvest destroys pupae in the soil.

For more information see:
Hornworms, The Real Dirt Blog
Tomato Hornworm, ANR

What's Hot in July

by Brent McGhie

What time of year and how often should bearded iris plants be divided?

Bearded iris plants should be thinned or divided in July or August every three-to-five years. Carefully dig up a clump of irises and then separate the rhizomes by cutting them with a knife or gently pulling them apart. Keep three-to-four-inch-long, younger, healthier rhizomes for replanting.

For more information see:
It’s Time to Divide Bearded Iris
Dividing Bearded Iris 

What's Hot in August

end rot on tomatos
by Brent McGhie

How can blossom end rot in tomatoes be prevented?

Blossom end rot is due to low levels of calcium in the tomato fruit, which is usually caused by uneven watering. End rot can be prevented with regular watering, amending the soil with organic matter and mulching to help the soil retain moisture. The soil can also be amended with gypsum, or another source of calcium, while heavy applications of nitrogen fertilizer should be avoided.

For more information see:
Tomato Blossom End Rot (pdf)

What's Hot in September

spider mites
by Brent McGhie

Is there a way to prevent spider mites in the garden?

Spider mites prefer dry, dusty conditions; so regular irrigation and sprinkling to keep dust down in the garden area will deter these pests. A more forceful spray on plants, especially on the undersides of leaves, can wash off dust and dislodge spider mites. Tolerating a low spider mite population provides food for the mites’ natural predators and can allow a natural balance between predator and prey to become established.

For more information see:
Spider Mite Pest Note 

What's Hot in October

monarch caterpillars on milkweed
Brent McGhie, photo: J. Alosi

Which species of milkweed should be planted to attract monarch butterflies?

Milkweed belongs to the genus Asclepias. The California native milkweed species that are most commonly available commercially and grow well in this area are narrow-leaved milkweed (A. fascicularis) and showy milkweed (A. speciosa).  Other native milkweed species that are not commonly available include California milkweed (A. californica), heartleaf milkweed (A. cordifolia), wooly milkweed (A. vestita), and woolypod milkweed (A. eriocarpa). All of these species will grow in Butte County and are suitable for monarch butterflies, whose caterpillars feed exclusively on milkweed plants. Coincidentally, narrow-leaved, showy and woolypod milkweed plants will be available at the Butte County Master Gardener Plant Sale on October 15 at Patrick Ranch.

For more information see: Xerces Society's
Milkweed FAQ. (pdf)

What's Hot in November

peach leaf curl
by Brent McGhie

How can leaf curl in peaches and nectarines be prevented?

Peach leaf curl is a fungal disease that attacks peaches and nectarines. The best way to prevent this disease is to plant resistant varieties of these trees. Nonresistant trees should be treated with a fungicide containing copper, or a synthetic fungicide. Look for the term “metallic copper equivalent” (MCE) on the label of copper products. Generally speaking, the higher the MCE, the more effective the spray will be. The synthetic fungicide chlorothalonil is currently the only synthetic fungicide available for treating peach leaf curl in backyard orchards. A single spraying when the tree is dormant is usually effective, but if it is a heavy rainfall year a second spraying just as the flower buds begin to swell might be advisable.

For more information see:
Peach Leaf Curl 

What's Hot in December

pruned peach tree
by Brent McGhie

When should peach trees be pruned?

Dormant pruning of stone fruits such as peaches, plums and nectarines should be done from mid-February to early March. Late-season pruning wounds heal faster than cuts made in fall or early winter. This means there is less time for disease-causing organisms to infect the wound. Apricots and cherries are more susceptible to water-borne diseases, so pruning during the dry summer months is recommended for these trees. Apples and pears can be safely pruned any time during dormancy.

For more information see:
Training and Pruning Fruit Trees (pdf)
The California Backyard Orchard