Q: Three years ago I bought a bonita ash tree because of its size, beauty, easy maintenance, and short period of leaf dropping. So impressed over the past year I was instrumental in the planting of four more in our little community. Once established how often do you feel they need to be watered?
A: The recommended water schedule for ash trees is once every seven to 10 days during the summer to a depth of 24 to 36 inches. In the spring and fall you can back it off to once every 10 to 21 days and in the winter every 14 to 21 days.
Also, I assume you are using drip irrigation arranged in a circular fashion around the drip line of the tree. When they are young you can get away with a hose at the base of the tree, but not once the absorbing roots extend farther out.
Q: I am looking for a yellow flowering vine I can grow in a large 36-inch pot. It is south facing with late afternoon west filtered sun. I’m thinking the primrose jasmine might be a good choice to grow up onto the wooden arbor we have on our south-facing arbor. What do you think?
A: I think you have a good idea. primrose jasmine (Jasminum mesnyi) is a sprawling evergreen shrub that has slender arching branches 5 to 10 feet long and bright yellow double flowers 1 to 2 inches across in mid to late winter.
It develops a vine-like growth habit when branches are tied to a trellis and allowed to trail down so your arbor would work well. It makes an attractive mounding foundation plant 3 feet high if cut back once a year. It grows best in full sun or part shade and is an interesting specimen plant with graceful cascading growth habit and early flower display.
Q: I recently removed a large amount of entangled vines and plants from around the back of my home. They had been there since before I purchased it in 1969. I would like to get rid of the roots before they start growing new sprouts so I can plant a garden. They cannot be dug out because they are really embedded into the house foundation. A friend suggested Round Up but I do not want anything toxic. I have two desert tortoises that live there, and a cat.
A: Roundup and similar products made with the active ingredient glyphosate are toxic to desert tortoises, among other things, so I am glad you asked before experimenting. Your best solution is the one you already used. Keeping the weeds under control by continued and persistent removal of the above ground green parts will eventually starve the plants.
Without the ability to photosynthesize, there won’t be any food to send to the roots and eventually they will die. Unfortunately, this doesn’t happen quickly much of the time, especially if the weeds have been growing since 1969. But don’t let that discourage you. If we could put a man on the moon, we should certainly be able to kill a few weeds.
Q: I just noticed your great pruning information in the paper, and I have a question. I planted this palo brea last year, in hopes that over time it would become a tallish beautiful tree that with a high arching branching pattern (surely at a minimum that we can walk under). The info you provided only addresses deciduous trees. I wonder if, when, and how to prune the branches. Also, any suggestion about staking so that it grows pretty straight up, or is that unnecessary?
A: The mature size of the palo brea (Parkinsonia praecox) is 20 to 30 feet tall with an even wider spread so I expect your hope for a beautiful shade tree will be realized in time. It’s hard to tell from your photo but it appears you allowed enough space for this desert specimen to reach mature size without any restrictions.
Because it spreads so wide, it isn’t for every landscape. Pruning shouldn’t be a big deal because it has adequate space. The normal pruning we give to trees to remove damaged, crossing, and rubbing branches should be sufficient. If you need more advice on pruning, please let me know.
Staking is typically done for the first year or so if a newly planted tree requires it. Trees need to be able to sway a bit in the breeze to develop the necessary trunk flare that will support it for many years to come. Staking too tightly and for too long inhibits this development.
