Has Spring Really Sprung in Your March Garden Calendar?
"Beware the ides of March" was advice given to Julius Caesar in the play by Shakespeare, and its advice that gardeners should heed as well. The ides (middle of) March represent one of the great transition states in gardening in California.
Your March garden calendar is the last month with significant amounts of rainfall and the risk of flooding during the spring, and early March is the last real chance for having a freeze undo all your hard work.
Take the usual precautions at the beginning of the month to prevent freezing and frost damage.
By most conventional standards, March is where the gardening season "really begins" – the work you did in January and February was preparation to make March easier. Most of March's tasks boil down to planting and fertilizing.
Planting Time Is Here!
Most of the nurseries have plants in bloom for you to evaluate, and it's easy to get a little bit overwhelmed looking at all the options. The first thing you should do is think about your landscape design plan – bring a sketch of it with you to the nursery, and look at what plants you want to put where, and when – so that you can stagger their blooming periods to get maximum enjoyment out of the springtime.
March is the best time to plant trees, shrubs, herbs and perennials in California. Make sure you cultivate at least a foot deep when you're preparing the planting beds.
This is the time to start planting from seeds; there's plenty of variety to choose from. This is a good time to start summer flowers and vegetables for April and May.
While the weather is changing, keep in mind that seeds and cuttings work better when it's warm out – it's worth it to hold off on that anticipation to 'dig right in' to prevent all your hard planting work being undone by a late frost!
When planting nursery trees and shrubs, be sure to dig a hole that's twice the size of the root ball – but don't dig it much deeper. Tamp the dirt back in to firm it up and provide stability to your new addition when you're done. You generally don't have to pack shrubs with compost material like you do vegetables.
And Time To Feed Them...
After your plants have budded and shown their first leaves, it's time to fertilize them, particularly for trees and shrubs, fruit trees, strawberries, roses and citrus. Use a fixed nitrogen fertilizer, but don't overdo it – fertilizer runoff is a major urban contaminant, and causes awful algae blooms in the rivers and out in the ocean, and a lot of plants – particularly those native to California, or from places with similar climates, don't need fertilizer. With modern fertilizers, most plants only need two applications in a year – the second one, in September, prepares them for fall and winter dormancy.
While we're on the subject of fertilizing, this is the time to fertilize your lawn; lawn fertilization is one of the key factors in getting the kind of lawn you desire.
Erratically fertilized lawns can experience a problem with rust and red thread and other fungal parasites. Putting enough nitrogen fixed fertilizer down means your grass will outgrow its competition.
You can identify it by the rust brown patches on your lawn. It'll rub off in your fingers and feel a little oily.
And Time To Weed
By the end of March, spring has hit, and everything's growing as fast as it can. That also means the weeds you don't want as well as the plants you do want. Dandelions and other broadleaf weeds will be migrating to your yard. If your neighbor has dandelions, you'll get them to.
Fortunately, dandelions and other broadleaf weeds are easy to control with spot spraying and you don't need to carpet bomb your lawn with herbicides.
The two brands we recommend are Weed-B-Gone and Trimec.
While there are other herbicidal sprays with the same active ingredient as Weed-B-Gone, be careful – most of them also contain Dicamba, which can damage trees if it's absorbed through the roots. This is another reason to be sparing in your use of chemicals in your gardening plan.
There is a major pest that isn't controlled by those two recommended products. It's Oxalis. Oxalis is vulnerable to Turflon, but you may need to have a professional apply it for you. Turflon is sold by the pint, but you only need a teaspoon per gallon for an effective spray.
As with many problems in life, weeds are best controlled while they're still small – apply a pre-emergent herbicide to your planting beds while you're fertilizing them and potting things.
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The Landscape News Flash
Your March garden calendar is the last month with significant amounts of rainfall and the risk of flooding during the spring, and early March is the last real chance for having a freeze undo all your hard work. 
March is the best time to plant trees, shrubs, herbs and perennials in California. Make sure you cultivate at least a foot deep when you're preparing the planting beds. 
While we're on the subject of fertilizing, this is the time to fertilize your lawn; lawn fertilization is one of the key factors in getting the kind of lawn you desire. 
Fortunately, dandelions and other broadleaf weeds are easy to control with spot spraying and you don't need to carpet bomb your lawn with herbicides. 
