As winter begins to wrap up it is time to start preparing your landscape for spring. There are many things that need to be done to the landscape before your plants start to wake up for the year. Timing is critical during this time of year to promote optimum grow and health of your plants.
Most people know that you should be cutting back perennials, grasses, and trees during the winter. However, most people do not know the timing of when to implement these practices. It is best to consult your garden book before doing any pruning, as every plant is uniquely different. Here are the basics:
Perennials: There are 2 types of perennials in regards to pruning; herbaceous and woody.
An herbaceous perennial is simply a plant that does not form wood. Most of these plants can be cut back by 70%. An example of this would be Mexican Sage (Salvia leucantha). It can be cut back very close to the ground.
Woody perennials cannot be cut back as severely. When pruning evergreen perennials cut back as far as you can until you get to the last few leaves on each branch. For example you cannot prune a Lavender back to the woody older growth. Woody perennials will not typically regenerate unless there are still leaves on the branch.
The most important thing to consider when cutting back your plants for the winter is frost. All plants have a different freezing point. For most plants it is best to wait until the last chance of frost. Leaving the dead parts of the plants until this time helps insulate the plants giving them added protection. The best time to cut back your perennials would be mid to late February in the coastal regions, Late February to early march inland, and mid to late March in the north county.
Grasses: The common myth is that in winter it is time to cut back your grasses. In most ways grasses are very similar to perennials. All grasses have different freezing temperatures. In regards to most grasses you should wait until the last chance of frost. There are only a few varieties of Carex that you would cut back. For these you can cut them back any time during the year and in some cases more than once. Others like the Purple Fountain Grass (Pennisteum rubra) is fairly frost sensitive and should wait until the very last chance of frost. Another common problem is how far to cut them back. No grasses should be cut all the way back to the ground. When this happens the center of the grass tends to die out. Take a look as you drive or walk around town. You will notice a lot of grasses that look like they are dying in the center and it is because they were cut back too far in the past. 6-8” should be low enough to promote healthy growth.
Pruning: Winter pruning is only for the Stone Fruits (Peaches, Plum, Pears, Etc.) and basically any deciduous fruit trees. Winter is not the right time to cut back citrus or Avocados. Every fruit tree is very different. Some trees fruit on second year wood, only first year wood, or long lived fruit spurs and even for the seasoned professional it can be difficult to remember. It only takes one bad pruning job to ruin a tree forever. I would recommend doing your research before pruning each of your fruit trees. There are many resources on the internet. One of the best is YouTube. There are video’s on how to prune each tree. There is also a book How to Prune Fruit Trees by Sanford Martin. It is a great inexpensive pocket resource for fruit tree pruning.
Dormant Oils: The other thing you need to consider during the winter is treatment with dormant oils to prevent insects and disease during the growing season. This is the time to spray your trees with either Copper Spray or Sulfur Spray. These sprays will reduce the diseases like “Peach Leaf Curl” or “Pit Rot”, as well as, many insects like Borers and scale. You must apply these oils before the buds begin to break into flower. I know that in parts of San Luis Obispo and the coastal regions it is too late. However, this can vary by tree species and localized climate.
February is the perfect month to get out into your yard and get ready for spring and a critical month for most of your landscapes health. So, get out there and get to work!