Now that the hectic pace of spring has come and gone, it’s easy to think that all the hard work is over. The planting, fertilizing, trimming and clean-up are all complete, shouldn’t we just sit in our Adirondack chairs and gaze serenely at the garden? We can’t forget one of the most difficult tasks a gardener faces, summer watering. With our Northwest summer drought, plants need consistent and thorough watering to grow and stay healthy.
I’ll never forget a Myrica californica that is growing in the arboretum. When I first noticed it a few years back it appeared healthy. The leaves were green. It had new growth, but it was small. We added irrigation to its bed and within a year it had doubled in size. After two years it has tripled in height and width. It’s a changed plant now, like it has a new breath of life with regular and consistent watering. I see its potential. It’s interesting that we might think a plant is doing just fine. It’s green. It grows a bit every year. And then suddenly when all its needs are met…wow! It can take off.
There are many methods available, sprinklers, watering cans, drip irrigation and in-ground irrigation systems with timers. Water is a precious resource and we should always be thinking about conservation. Setting up a home irrigation system such as drip irrigation may seem complex, but is really quite manageable. The main thing to remember is that plants prefer a thorough deep watering to a light superficial sprinkling. When we spray the surface, the soil may appear dark and moist, but underneath the roots have no moisture. We have to allow time for the moisture to reach the root zone. Water when the soil dries out, more often when it’s hot and less when it’s cloudy and cool.
It’s happened so many times. I think I’ve watered a container really well, whether a small four inch pot or a large patio container. I might have to dump the soil out or dig into the container, and I’m shocked to find out it’s dry at the bottom! A good method is to water a container until the water runs out of the bottom. I also like to give a container as much water as I think it needs. And then do it again. Give it twice as much. If the soil is too dry it can become hydrophobic and it takes a long time to absorb the water. Then the container will have to be watered two or three times. Over-watering can be a problem too, but only if the soil constantly remains wet and is never given the chance to dry out.
Planting similar groups of plants together can also help conserve water. Annuals and big leafy perennials take more water than established shrubs and trees. Keeping them in separate beds will make watering easier. Many of our Northwest native plants are tough and drought tolerant, but remember this is only after they have had a few years to grow a good root system. So when you add any new plants, even if they are ‘drought tolerant’, remember to water for the first two summers. Mulching is a good idea as it helps retain moisture. Rhododendrons are usually ignored all summer, but these plants will really benefit from a consistent supply of water. Remember, a healthy plant that has been well watered and fertilized will more easily fight off insects and disease. Just like us, if we aren’t getting enough sleep or eating well we tend to get sick. So enjoy your summer garden and don’t forget to give your plants a drink. And then do it again.