Photo By: COURTESY OF KELLY BOWMAN GREENWOOD
To extend the life of garden plants, monitor the amount of water they receive. Controlling water can be far more important to their health and longevity than any type of amendment or pest control.
Maintaining your garden design may involve ripping out that giant lavender you’ve loved for years and replacing it with exactly the same thing.
Yes, you read that right.
Here in California, where we garden with an array of perennials, many garden favorites have a shelf life. There’s really no exact expiration date marked on that lavender, but if it’s been in your garden more than five years and it’s looking tired and woody, that’s because it is.
If you have a well-organized garden and love the role that favorite plant plays, there’s no need to rethink your design plan. Just recycle that puppy on the compost heap and plant a new little one from a 4-inch pot or 1-gallon container in the same spot. Your neighbors replace their beds of water-loving annual pansies or petunias every year. Your perennials create a much longer-lasting and potentially more waterwise flower border, but at some point, they need to be replaced, too.
Annuals are exactly what they sound like – plants that live one year. Woody shrubs are generally much longer-lived, 10-100 years, depending on the plant type. Perennials are flowering plants that tend to fall somewhere in between, in the three- to 10-year range.
So the first order of business is to know what the plant is and the role it plays in your overall design. If you don’t know what it is, identify it so that you know its typical lifespan.
There are many things you can influence in your garden with amendments, but age is not among them. Many plants adapted to Mediterranean, summer-dry climates like ours in the Bay Area have survived because they have short lifespans and can reproduce quickly. They just keep pushing out flowers until the rains stop.
Except now, thanks to irrigation, they don’t.
That means knowing when to fold is a key part of California gardening. Having appropriate expectations for the life cycle of your plant makes it easier to part with it when it’s time. And timely replacement of perennials can be an important element of maintaining the design of your garden. It might be helpful to think of them as the marathon runners of your garden.
Knowing when, or if, to feed
Generally speaking, most well-adapted perennials – especially dry California natives – do not want to be fed. This would be akin to sitting your lanky marathon runner down at an all-you-can-eat buffet, where the vegetable of the day is broccoli cheese casserole. If you want them to make it through season after season, they need to run lean, on unamended soil.
In a garden setting, controlling the amount of water applied to plants can be far more important to their health and longevity than any type of amendment or pest control.
Mediterranean plants are adapted to going days, sometimes weeks, without water during the summer. If you give them a little extra, they’re going to be thrilled and will continue to bloom for you, long past the time when they might naturally have gone dormant. Give them a lot, and they’re going to go into overload. Watch your plants carefully through mid-spring and early summer. If those tall, waving perennials start to relax to the ground, they’re getting too much water, which will kill them sooner (due to rot) or later (from overgrowth).
If you don’t have time to think about your garden water, purchase a smart controller with soil sensors or a weather station to control your watering schedule. Otherwise, your eyes and your fingers are the best judge of plant health and soil moisture. Dial your irrigation timing and frequency up or down throughout the season to respond to the weather and the condition of your plants.
Identifying the age problem
If a plant is overwhelmed by pests, it’s probably not the right match for its place. If it’s wilting, diseased or showing signs of rot, age is likely not the problem. Research the problem or contact someone knowledgeable for help (such as the local UC Extension Master Gardeners) to fix the environmental conditions or determine a more appropriate plant with which to replace it.
On the other hand, if your valiant little perennial has performed beautifully but is now looking hollow in the middle, perhaps still attempting to bloom on one side, it simply may be at the end of its rope. If it shows no signs of infestation or disease and just looks stringy and pathetic after a few years, it’s perfectly appropriate to replace it with exactly the same thing.
Kelly Bowman Green has been designing Bay Area landscapes since 2002. She is a member of the Association of Professional Landscape Designers and has appeared on HGTV’s “Landscape Smart” and “Small Spaces, Big Style.” For more information, visit www.greenwoodlandscape.com.