Water Wise

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It seems like water has been a subject that I at least touch on every few months in these articles and it is about time to revisit the matter once again. Why cover it so often? Mostly because we are all on this journey together, constantly learning and upgrading our skills and technique. 

For many of us, getting our first cell phone was the un-tethering of our lives (Now we are glued to it). We were able to call in grocery lists, or make that flat tire call. Then all of a sudden, we could take pictures and send a text message. I actually purchased my first iPhone so that I could more easily send texts. That phone served me well beyond it’s like expectancy. It was a 3gs. That tells you something about me. I am not usually a first adopter to technology. I mean, it took three generations for me to jump on board. I upgrade only when it serves my needs or the darn thing wears out. But the time came, and I upgraded to an iPhone 7. Yep. Four generations there. Then within a day I thought it was the most marvelous piece of technology that I had ever touched. Everything worked the way that I thought it should, intuitively. I could do the things I needed to much easier. But enough about the iPhone. Now about watering. It’s time for another upgrade.

I changed my watering practices a bit this year and the results are stunning. My trees are growing better and stronger than ever. That is partly due to a better fertilizing regimen, but also due to better watering practices. Of course, you have to throw the rest of the bonsai skills in there – repotting being the major one – doing it properly. Then there is pruning – the right amount at the right time, pinching, etc… 

But it all comes down to watering. What is the difference this year? In a phrase, it’s not overwatering. Now that has been really tough, having gone through the wettest winters on record. But I can’t control that in my situation. Unless you have a covered area, you can’t either. But all the trees survived that better than expected. The key this year has been to check water a couple of times a day – not an easy feat for those of you who commute to work. I commute about twenty feet down the hall, so I can check water when needed. I usually like to check twice a day, once about 10-11 am and again in the afternoon. Sometimes I do it three times a day, which would be better. Above 90 degrees and I am definitely checking three times.

But all that is the same as I have been doing for five years. What is different is not watering everything, all the time. I now pay much more attention to each plant and how it is using water from day to day. I have some Magnolias in full sun and they are barely using one full watering a day. So sometimes, I skip two waterings on them and wait until they have used up what they have. 

On the other hand, I have a Rocky Mountain Juniper that sucks water like there is no tomorrow. Nick Lenz in his book about native trees for bonsai said that he gives his RMJs just a whiff of water at a time. Why then is my tree sucking the pot dry? Water and oxygen balance. MyRocky has doubled its foliage mass this year. That’s no mean feat for an RMJ. It is obviously cranking on all cylinders. But I still wait for the top of the soil to dry a bit before I water it again. The point is to give the tree all the water it needs, but no more. 

I used to water everything the same and somewhat control the water by the particle size of the soil – fine particles for shohin, coarse particles for pines, especially five needled pines. But that led to some trees being overwatered, or not enough. So now I drench each tree that I am actually watering, to make sure I get plenty of water into the shin, the soul of the tree, right under the trunk. Or I don’t water at all. The danger I used to have was applying just a light coat of water. When I thought the tree was wet on top, it was really dry inside the pot. Those now dry roots die, then rot because they can’t uptake water anymore and are drowning in it. So once the cycle is started, it takes diligent effort to correct.

I have been able to significantly improve the health of several trees this year that were flagging by limiting the amount of water they receive. Just paying closer attention and being patient for them to grow on their own terms. I have to figure in several factors.

1.  Overall health of the tree. How well and how rapidly is it growing.

2.  Size of the container relative to the size of the foliage. Depth plays an important part here.

3.  Species of the tree. I am watering single-flush long needle pines – which are all alpine species, like Ponderosa, Limber, and Lodgepole only once a day. My azaleas and maples are never allowed to dry out.

4.  Daily weather – hot and windy, or wet and cool?

5.  Position in the garden. I have trees that get morning sun and afternoon shade, and the opposite. What condition is it moving into?

6.  When can I water again? It has to do well until I can get back to it. Better to give a healthy tree extra water than let it dry out.

Now that we are entering into the summer in earnest, many trees are hardening off, forming a cuticle on the leaves that limit moisture loss. Some are even going dormant. They are not rapidly expanding, so even though the temperatures are going up, the amount of water is going down. I have really noticed this in the last week or two on some trees. More or less, conifers. 

On other trees, especially ones that were heavily pruned in late spring and are now in their second flush of growth, are showing no signs of slowing and require even more water to keep them from burning. As a hint, I moved some deciduous trees that were growing slowly into a bit of shade and they are really taking off. That means that they are using more water in the shade than they were when in full sun. Go figure.

Am I taking any more time to water than before? Not really. My collection takes only about 15-20 minutes each session. I learn to evaluate the water conditions quickly and move on. I know my trees, and what to look for in each one. I get to spend a little time with them everyday. Last thing. Be sure to have a few bonsai buddies on tap for watering when you leave for more than a day. Help each other out. See you in September. 

Scott Elser