Buying plants from a nursery is a regular part of managing a park, whether the plants are exotic ornamentals or natives used in restoration projects. But once in a while, you get something different from what you ordered, or something in addition to what you ordered.
In this first image, you see a sweet little plant from the carrot family. It is called Erigenia bulbosa. We found this on the south side of the Reservoir growing in a bed of native pachysandra (Pachysandra procumbens). The common name for this plant is Harbinger of Spring because it blooms so early. Although this plant is native to the northeast, it is not native east of Binghamton, New York. Our best guess is that it came in soil with the pachysandra that was planted. It may or may not persist in the Park, we will have to wait and see.
This next species is also likely to have hitched a ride in the soil with species planted in the Park. This is Euphorbia cyparissias, cypress spurge, which we found growing at Cherry Hill. It is a lovely ornamental from Europe, but it is a weed and so can easily show up in plants purchased at a nursery.
Some species are very similar in appearance and it is easy for nurseries to make mistakes in plant identification. And once the plant is in production, it keeps being sold under the wrong name.
This photo shows Viola striata, a lovely native violet. However, when I ordered the plant (back when I was working in the Park), I had ordered Viola blanda. Viola blanda is another native that looks very similar. One difference is the upper petals of V. blanda often twist or bend backwards. Also, Viola blanda are stemless and very low-growing. In this case, there was no problem with the misidentification, both are native white violets that grow in similar habitats.
Sometimes a misidentification by a nursery can be problematic. Years back we ordered Alnus serrulata, smooth alder, a native species. Instead we got Alnus glutinosa, black alder, a European species that is invasive. It took time for the small shrub to mature, but now that it is producing fruit we can see that we have the wrong species.
As I have mentioned in earlier blogs, a survey of the flora of Central Park was done in 2007. Herbarium specimens were collected for many of those species. This next plant is a good example of why herbarium specimens are important. When Daniel and I were looking through the specimens of the 2007 collection, we came across one labeled Virginia creeper, Parthenocissus quinquefolia, a common native vine used in restoration projects. However, Daniel immediately recognized from the flower of the pressed specimen, that this was not P. quinquefolia, but rather P. inserta, grape woodbine. The two species are very similar and it is an easy mistake to make. The reason science works is because scientists make their data available to others for verification. It's always satisfying to add another species to the flora of Central Park, especially a native one! This was a nice find, as we now have another native species on our list and the 2007 list.
We looked in the field in several places, and sure enough, both species are present, sometimes growing side-by-side.
Nurseries need to know the difference between these two species for a good reason. Both are native and neither are invasive; but only Virginia creeper can climb. The image below shows the suction cup discs that are formed on the roots of Virginia creeper as it is climbing up the tree. Grape woodbine does not do this. So if a landscaper is looking for a vine to climb a wall or other structure and gets grape woodbine instead of Virginia creeper, she will be very disappointed.
This last species, is one of the milkweeds, Asclepias purpurascens, purple milkweed, pointed out to us by Conservancy staff. Daniel and I almost did not document it because we thought it was a new restoration species the Conservancy was trying. But after checking with the Woodland staff, we learned that no one planted it. This species has seeds that are wind dispersed so it is unlikely that it came in on its own, there are no populations near enough to spread to Central Park. So this one also is likely to have come in with other plant material. A nice hitchhiker to have arrived in the Park.