Landscape Conifer Foliage: Four Examples
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It can be a challenge not to confuse one thing with another when you’re dealing with landscape conifers such as arborvitae, Leyland cypress, Arizona cypress and falsecypress. But the differences are there, and with a little patience and experience you can become a lot more confident about the unique appearance of each. Details matter, as can be seen in the foliage closeups below.
Clockwise from top left we have a variegated Chamaecyparis pisifera (Japanese falsecypress), Hesperocyparis arizonica (Arizona cypress), x Hesperotropsis leylandii (Leyland cypress), and Thuja occidentalis (American arborvitae). They not only appear to be different, but there are some specific points we can highlight to qualify those differences. To get started, note that the lateral pairs of scale-like leaves on Chamaecyparis pisifera have long, tapering points and also project outwards just a bit. The darker-colored resin ducts are also very visible on the individual leaves. Hesperocyparis has a neater, more orderly arrangement of foliage, with the leaves appressed (close up against) the branchelet, and not splaying outwards as with the Chamaecyparis. (Bear in mind that across Chamaecyparis genera, this characteristic is highly variable.)
The Hesperocyparis leaves also closely overlap one another, with the upper tip of the leaf below overlapping the bottom of the next leaf up. Finally, on this particular Hesperocyparis cultivar, the foliage is glaucous, or (mostly) covered with a waxy bluish material that can be rubbed off with the thumb (as with the individual needles of Colorado blue spruce).
Next is x Hesperotropsis leylandii, which has somewhat flatter foliar sprays than Thuja, but also has another interesting feature that separates it from our other examples. Note the juncture between two lateral leaves, indicated by the red arrow. You can make out a right-angle just at the point where these leaves split away from each other.
Finally, Thuja occidentalis leaves could be seen as more ovate than the other three, with pustulate resin glands that result in a more rounded or convex appearance of the leaf pairs along the branchelet. The overlapping individual leaves appear more appressed to the axis of the branchelet than those of either Chamaecyparis or x Hesperotropsis.
We haven’t hit everything of botanical significance, by any means. But these easy examples help to demonstrate that a closer look is all you need to start separating plants that, on the surface, may appear to be all the same thing.