Seedling variability is more pronounced in some
species and only requires a casually curious eye to see the differ-
ences. Perhaps there is no better example of this variability than
in Nyssa sylvatica, commonly known as tupelo, black tupelo,
black gum, tupelo gum, or sour gum. This tree has always been
a favorite of mine, but seedling-grown trees can be broadly dif-
ferent in form, leaf, summer and fall color, and other attributes.
Some seedling tupelo trees are full and dense; others are
tall and narrow. Some take on a weeping appearance, while
others seem to be confused as to what form they want to
take. Leaf size, form, and branch orientation vary, and fall color
ranges from incredible to spectacular, but is seldom poor. The
species form is a slow-growing, medium to large maturing
tree about 25 feet (7.6 m) wide and up to 45 feet (13.7 m) tall
in an urban location. Helpfully, it's genetically predisposed to
deep root growth, making it less likely to heave pavement.
Before tupelo cultivars were widely available, I was involved
in a street tree planting project that required more than fifty
Nyssa sylvatica for a neighborhood planting in Snoqualmie,
Washington. Only seedling trees were available, and I had
the opportunity to select and tag them at a local nursery.
I was wary of the seedling differences; my goal was to
select all of the 2-inch (5-cm) caliper trees with as close to
the same form as possible. During the selection process,
I thought I had found many that were very similar.
However, over the many years following that planting, I observed
and confirmed that seedling-grown Nyssa trees provided a
plethora of canopy structures and forms too wild to describe!
Good friend of mine, Snoqualmie, Washington Urban Forester
Phil Bennett, can attest. Every fall, he and I inspect these trees
to admire, frown, and chuckle at the natural variations that
occur in this species. The weepers can be especially challenging
to manage as street trees. We both loved Nyssa sylvatica for its
general attributes for urban planting but were frustrated by the
extreme variability of its seedling-grown form (see photos). >>
Tremendous seedling variability of Nyssa
sylvatica on the streets of Snoqualmie,
Washington reinforced the need for cultivar
development. Photos by Jim Barborinas
30 CityTREES
