What’s hydrozoning? It’s grouping plants with similar water needs. You put those plants next to each other, or you put them on the same irrigation line. And I haven’t always done it — to my great irritation, and to my plants’ hardship.
Here are three examples of times that I haven’t grouped plants in my food garden well, along with how I’ve corrected or mitigated the mistakes. Maybe they can help you design the plantings and irrigation in your yard better.
Cherries with avocados
A couple years ago, I planted two cherry trees (Lapins and Royal Crimson) near some avocado trees. (See the photo above.) Because of the proximity of the trees, I just added the cherries to the irrigation line of the avocados. The main problem with this was during the winter when the cherry trees were leafless and needing no water while the avocados still had a full canopy and sometimes needed water when the rains were too far apart.
It is not ideal to have deciduous fruit trees on the same irrigation line (schedule/station/valve) as evergreen trees. In order to keep both types of trees healthy you either overwater the deciduous fruit trees or underwater the evergreen fruit trees. I had chosen to overwater the cherries in order to keep the avocados happy. But finally, last year I corrected my mistake by running a long poly tube to connect the cherries to the irrigation line that my other deciduous fruit trees are on, thereby taking them off the avocado line.
An alternative correction in this situation would have been to insert a shutoff valve into the line going to the cherries, which I could turn off just for the winter.
Citrus with avocados
I did exactly this on an irrigation line along my driveway where I have both avocados and citrus trees. The water needs of these two types of trees are similar, both being evergreen, but occasionally the avocados need some extra water during heat waves. With the added shutoff valve, I’m able to give them that while not wasting water on the citrus trees.
You can add shutoff valves to the sprinklers or drip lines of individual trees, or you can insert one in the main poly tube between groups of trees. In this case, I added one shutoff valve between the avocados and citrus. (The line runs up the driveway so the citrus trees are “behind” the avocados.)
Blueberries with vegetables
I planted my blueberries within my vegetable garden so they’re all on the same irrigation line.
For a few years, I also watered both the blueberries and vegetables on drip lines.
They all performed acceptably, but I found that the blueberries sometimes looked parched in the heat of summer, as if they needed more water. At first, I added more drip emitters for the blueberries. Later, I switched to using sprayers on the blueberries instead of drip and the bushes seem to like that method of irrigation more.
Moreover, the sprayers on the blueberries have tiny shutoff valves that allow me to adjust the water output. As the bushes grow, I can easily turn up the water volume.
These sprayers work fine on a line that also uses drip emitters because they both need about the same water pressure to function properly. Mixing these methods is a convenient way to get some plants on a line more or less water than others.
Sometimes I wish I were a farmer of a 100-acre monoculture of only tomatoes rather than what I am, a gardener of a slice-of-an-acre polyculture growing 100 different plants. The watering would be easier.
Yet by grouping these plants as much as possible according to their water needs — hydrozoning — we can make our gardening lives a little easier. And when hydrozoning isn’t possible or practical (maybe it’s too late because the plants are already in the ground), we can mix irrigation methods and we can add shutoff valves in order to give our fruit trees, berries, and vegetables approximately how much water each needs.
(You might like to read my post: “Growing blueberries in Southern California.”)
A list with links to all of my Yard Posts is HERE.