I will never forget my first foray into plant diagnosis. Neighbors in Houston offered me a couple of nearly dead azaleas if I wanted to try to resuscitate them. I took the bait, dug them up, and schlepped home some sad specimens. They survived and eventually thrived because I spent the time to research why they were so miserable. Seeing the results set me on a new career path and 39 years later, I’m still learning how to make my plant friends happy. Now you can benefit from the travails of those sad azaleas, but don’t try to plant them here.
Some of you, like myself, are relatively new to Trinidad and Colorado. You may have come from an area where all you need to do is stick a plant in the ground and it grows. Woe unto you if you follow that philosophy when walking around the plant selection at a big box store! Azaleas, rhododendrons, and blueberries will not grow in the ground here because the soil pH is alkaline instead of acidic. Combine the high pH with constant winds, low humidity, and rapid changes in winter temperatures… Congratulations, you have just bought a Future Dead Plant. Do yourself and the local economies a favor by supporting local nurseries that carry the appropriate plants for this region.
Getting back to the azaleas, my neighbors had not examined the plants before they made their purchase. How did I know this? The plants had girdling roots and the root ball still looked like it had just come out of the container. Girdling roots can be a serious issue, especially for the long-term health and safety of a shade tree, because the upper root will eventually “strangle” the lower root.
In addition, the plants had been in the container so long that the root ball had nearly become an impenetrable mass of circling roots. Those circling roots will not move out into the surrounding soil unless you encourage them by making a few vertical cuts that will encourage new root formation. Don’t hack the root ball to pieces and make sure your cuts are clean, not jagged.
What else did I learn from the azaleas? Plant at the right depth, which means locating the root flare (swelling at the base of the trunk) to use as a guide. The neighbors had planted them too deep because I found the root flare and the trunk above the flare was stained from soil and water.
Roots are just like us in that they need oxygen to survive. Planting too deep pushes out oxygen and encourages waterlogging of the trunk, a perfect recipe for disease. In their defense, the neighbors had attempted to do their best because they had stuffed the planting hole with peat moss. However, that only pulled the water away from the root ball.
Amended soils are usually more porous than the native soil, and they wick away the water from the root ball. That’s the same principle in effect when you grab a paper towel to wipe up a spilled liquid.
Roots are also like us in that they can be lazy. They will stay in the “fine dining” area of amended soil instead of moving out into the more lean native soil, so please don’t encourage this slothful behavior. The only time I add a small bit of compost is when the soil test shows that soil organic matter is below 5 percent.
Finally, the azaleas were planted in full sun against a brick house with nary a bit of mulch to be seen. Mulch is your friend. It will help retain moisture, cut down on weeds (except for that nasty bindweed), and lower your water bill. Be sure not to pile the mulch up against the trunk, or you’re back in the waterlogging situation again.
Now that some basic plant health care has been addressed, upcoming articles will be about plants that are currently in bloom. This will give you an idea of what you can plant to have season-wide interest. In the process, I’ll throw in some design tips as well.