Q: Can you tell me if this tree is a cedar of Lebanon?
A: It looks like a deodar cedar (Cedrus deodara) from a distance. Cedar of Lebanon (Cedrus libani) branches usually form level layers in a mature tree. The deodar doesn’t usually look as layered and the branches and the leader tend to droop at the ends.
To be sure, you can count the needles in a cluster and you can measure them. The cedar of Lebanon has clusters of 15 to 45 whereas the deodar cedar has clusters of 20 to 30 so there is some overlap but if you can find some with greater than 30 needles that is a good clue.
Of the three true cedar trees in the genus Cedrus, the longest needles belong to the deodar cedar. If most needles exceed 2ƒ centimeters is likely a deodar cedar.
Q: Today I spoke with two lovely ladies at the Oro Valley Farmers market. I asked about this flower that grows wild in my yard. When I first saw it I thought it was a form of dandelion, but it has a gorgeous iridescent white bloom that opens at dusk. The hawk moths love it. The seedpods are plentiful right now, all dried up at the base of the plant. I’m including some pictures to help identify it. One woman showed me a photo of a birdcage primrose, however I’m thinking it is just an evening primrose.
A: There are a few species of primrose so it’s easy to get confused. I checked with our friends at the University of Arizona Herbarium and they think it is Oenothera caespitosa, commonly known as tufted evening primrose and fragrant evening primrose. This low-growing perennial is found throughout the West in sunny, dry, infertile, rocky, well-drained soils. It requires little water, which makes it a good choice for xeriscape gardens. Moderate watering will keep it blooming all summer.
Q: Do you have any info that would help our HOA organize its response to its fountain grass infestation? Also, are there any fountain grass variations that local nurseries sell that are sterile and won’t spread?
A: Fountaingrass (Pennisetum setaceum) is a fast growing, attractive, perennial, fire-adapted bunch grass and in our ideal environment can reach several feet tall and wide. It does just fine in dry environments although some rain helps. Unfortunately, it invades desert areas and readily outcompetes native species.
There are some varieties that are purported to be sterile but research shows they’re not 100 percent sterile and that’s a deal breaker considering it is invasive. Since it is a noxious weed in dry areas like ours I recommend removing it when possible, spraying with herbicides when necessary, and not planting it again. As is sometimes the case with invasive plants, humans are guilty of planting this species before we knew it was invasive. When it was first introduced, it was thought to be just another pretty grass for medians and landscapes.
