April in the Garden

April is National Gardening Month!  This month is the height of flower shows and garden tours in SoCal.  Every year is different, depending on weather and rainfall, so flower shows never get boring.  Remember, if you are entering growing plants in a show, clean out detritus around the plant for better showing.  Clean off the outside of the pot, too.  The judges pay attention to that kind of thing.

Garden Prep:
Weed, weed, weed.  It’s important to catch the weeds while they are still small because they will compete with your other plants for nutrients, water, and light.   As the saying goes, “A year of seeds means decades of weeds.”

Mulch a two-inch layer of organic matter around your annuals, perennials, trees and shrubs to suppress weeds, and hold in moisture.  When the weather warms up it will also keep the roots cool.  Mulching around roses is a great way to keep them evenly moist and help prevent fungus growth by reducing water splashing and spreading spores.  NOTE: Don’t mulch around warm season vegetables right now because they really need the heat around their roots.

Planting:
By mid-April we’re moving into the warmer time of the year and we need to plant accordingly.

Look for warm-season seeds in nurseries and get them started soon.

Annuals To Plant: Ageratum, Amaranthus, Aster, Bedding Begonia, Bedding Dahlia, Candytuft, Celosia, Coleus, Cosmos, Gloriosa Daisy, Impatiens, Lisianthus, Lobelia, Marigold, Nasturtium, Petunia, Phlox, Portulaca, Sunflowers, Sweet Alyssum, Verbena, Vinca Rosea

Perennials: Most perennial plants may be planted this month with good success.

Vegetables: Beans, Beets, Carrots, Cantaloupes, Corn, Cucumbers, Eggplant, Kohlrabi, Leaf lettuce, Lima beans, Okra, Parsley, Peppers, Pumpkins, Radishes, Summer, Tomatoes, and Watermelons

Watering:
Rain has been scant this year, so pay attention to your irrigation needs. With all the new growth on our plants, it’s important not to let them dry out if we get some hot weather.

Roses need about 1½ inches of water twice a week this month.  They are working hard right now with all the blooming that’s going on!

Citrus should be watered deeply about every week and a half to three weeks, depending on weather conditions, maturity of the tree, and soil type and drainage.  Shallow watering encourages trunk rot and it is important not to water the trunk of the tree when possible to avoid fungal disease.  A good rule of thumb comes from gardening guru, Pat Welsh, in her new book.  The rule is to water one-third the distance from the trunk to the drip line and an equal distance beyond the drip line.

My epiphyllums are budding now, so I expect blooms in a month or so.  The flowers on these plants only last a day or two, but are real show-stoppers in a variety of yellows, oranges, reds, pinks and all the colors in between.  Cut off faded blossoms and mist frequently in hot weather but don’t over water.  A good rule of thumb is to water when the soil is dry down to 1-1/2 inches.

Fertilizer:
Plants are going into a big growth period so continue fertilizing, but don’t be heavy-handed so that your plants don’t go into mega-growth mode, resulting in softer growth and a thirstier plant.  Plants growing with yellowing leaves with green veins are suffering from iron deficiency so an application of fertilizer with chelated iron would be a nice treat for the plants.   Roses need to be fertilized this month.  A half strength of 10-10-10 fertilizer will give them a nice boost.

Iron deficiency systems show up in plants as yellowing leaves with green veins.  Overwatering is a common cause.  This is a classic problem in roses, eucalyptus, camellias, citrus, gardenias and hibiscus.  Feed iron-deficient plants with a fertilizer that contains chelated iron combined with zinc.

Start feeding your camellias, azaleas and rhododendrons with an acid fertilizer when they stop blooming.

Pest & Disease Control:
Warmer weather means that garden pests are waking up, stretching and getting ready to feast on all the new, fresh growth in your garden.  Aphids are starting to appear in my yard so I’m blasting with water first, but if I see the problem getting out of hand, I will be a bit more aggressive with an insecticidal soap.  I keep a bottle of SAFER handy so I can spot treat when needed.

Head out to the garden in the early morning or evening to find snails and slugs. They are out in force and can do so much damage in a short period of time.  If we have damp nights, hunting is usually very fruitful!

Watch for caterpillars and stay ahead of an infestation. Some caterpillars will turn into beautiful butterflies, so don’t over react when you see your first one or two.  Just pay attention to those plants that tend to get infested.  In my garden, that would be my Cecile Brunner roses, tomatoes and geraniums. My first line of defense are my birdfeeders.  My theory is that if I attract birds to the garden and let the feeders empty out every couple of days, the birds will look for other food, i.e. caterpillars and aphids, on the plants in my garden.   If that fails, I’ll spray with BT – Bacillus thuringensis or Spinosad.  These will kill caterpillars only, leaving beneficial bugs alone.

Pruning:
Spring bulbs have all but finished blooming so they aren’t looking so great. It is SO tempting to pull those messy leaves out, but you need to let them die back on their own.  The bulbs are pulling nutrients from this greenery so you have to be patient!   Daffodil leaves can be twisted around and tied in a knot for an interesting and tidier look.

Frost damage wasn’t a huge problem this year, but if you do have frost damage, prune away the dead foliage only when you start seeing new growth.

Roses are starting to bloom now and you can encourage longer blooming by cutting flowers regularly. Whether you are cutting for bouquets or deadheading, cut above one of the first 5 leaf nodes that faces outward so future growth will be on a strong stem in an outward direction; otherwise, your later blooms will come on a weaker stems the next time around.   Sweet peas will also bloom longer if you keep cutting flowers.  Spread a bit of springtime by sharing your flowers with neighbors!

If you have naturalized poinsettias, it’s time to prune.  Cut back the past year’s growth to two joints from older wood.

Prune spring flowering shrubs such as azaleas, camellias, forsythia and lilac when they finish blooming because they bloom on year-old growth.

Miscellaneous:
Nurseries and garden centers are overflowing with plants.   Weekend gardeners are out in force, feeling energized by the warmer weather.  Veteran gardeners are scouring for new and interesting things to try in their gardens.  Buying small plants can really stretch your dollar, but once in awhile it is fun to splurge on a bigger plant to fill in a specific area or pot.  Look for compact plants with healthy looking leaves.  If they look wilted or rangy, they might be root bound or light-starved.

Take a walk around your town and enjoy the gardens that are thriving in our great climate.   Don’t forget……..SUNSCREEN!   HATS!   GLOVES!

HAPPY GARDENING!!!

Credit where credit is due: This monthly garden chores compilation comes from a lot of resources, past and present, including: Sunset Magazine, Union-Tribune, San Diego Floral Association, San Diego Horticulture Society, San Diego Home & Garden, Anderson’s La Costa Nursery, miscellaneous tidbits found on the web, in the library, from fellow gardeners, and personal experience in the garden.