Planting for Diversity was the first talk I’ve attended at Spring Grove Cemetery & Arboretum. A few years ago, I was at Spring Grove multiple times per week in nice weather and a few times a month in the winter. I went all the time! I think it’s one of the most beautiful, peaceful places in Cincinnati. My husband and I still like to go as often as we can to walk around and practice some photography.
I just recently realized that they offer talks on horticulture topics. I’ve done tree IDs with groups there before, but nothing officially given by Spring Grove staff. It was great! I’ll definitely be checking their calendar often to see what’s coming up. They have a lot of history, experienced people and land to manage, so there’s tons of good information to be had.
There was a lot covered in this talk! The first part provided some interesting information on the planting diversity problem we’re setting up for ourselves. The second part went into specific species that would be great choices for diverse plantings.
The Diversity Reality
We’re setting ourselves up for problems – like what happened with the ash & ash borer. Spring Grove was hard-hit by the ash borer. When the beetle first arrived, they had over 500 ash trees in their undeveloped acreage. They chose 200 trees to protect with routine treatments and now 7 years later have in the high 180’s of those treated ash remaining.
Landscapers and cities are using too many of the same plants and monoculture plantings. Two of the big ones right now are maples and blue spruce. Cities are particularly negligent, planting only a few types of trees in an large area. The average age of a city street tree is just 7 years. This is due to disease, improper conditions, not matching growing site to growing habit, etc.
Cities have their reasons for using what they do. A lot of time they are limited by what they’re allowed to plant and what looks good. Sometimes invasive species are chosen because they adapt to a site really well or are more robust than other options. We were given some examples of planting diversity in cities around the US:
- NYC, NY: Lots of maple varieties, including the Norway Maple, which is invasive and spreading into the natural areas surrounding the city. Callery pears are common, and also invasive. 20% or more of what is planted in New York City is invasive.
- Seattle, WA: Norway and Red Maple, Hawthornes, Flowering Cherries
- Phoenix, AZ: Thornless Honeylocust, Arizona Ash, Chinese Elm, Arizona Sycamore, Chinese Pistachio
- Cincinnati, OH: Crabapples, Honeylocust, Zelkova, Oaks, Maples, Elms
The big picture problem is that cities from the East to the West coasts are planting masses of the same types of things. Unfortunately, it’s the perfect setup for a major pest or disease event to spread rapidly across the county, like continues to happen with ash.
Recommended Choices for Diversity
So, what should we plant? There were SO many recommendations and details on special characteristics like fall color, soil conditions and size. I’ll highlight some of the families and notable mentions.
- “Can’t go wrong with Oaks”
- Quercus coccinea (Scarlet Oak)
- Quercus lyrata (Overcup Oak), cultivar “Highbeam”
- Good for wetter areas
- Quercus muehlenbergii (Chinkapin Oak)
- White, hardy, tiny acorns so not as much debris
- Quercus prinus (Chestnut Oak)
- Quercus velutina (Black Oak)
- Shiny, pretty leaf, good for wetter areas
- Carya ovata (Shagbark Hickory)
- Need to site correctly
- Carya illinoinensis (Pecan)
- Great landscape and shade tree
- Carya cordiformis (Bitternut Hickory)
- Native hickory, smaller fruit, good fall color
- Gymnocladus dioicus (Kentucky Coffeetree)
- Note: May look pathetic at nursery when it’s small, but turns into a gorgeous tree. “Espresso” and other male clone cultivars won’t have as much mess to clean up.
- Taxodium distichum (Bald Cypress)
- Good for lake edge setting or clay hill
- Deciduous conifer
- If it’s not near water, it won’t get Cypress Knees (however they might if near strong irrigation/sprinklers!)
- Dawn Redwood or Pond Cypress won’t have knees even in water setting
- Peve Minaret Dwarf Bald Cypress
- Much smaller version
- Weeping varieties
- “Falling Waters”
- “Cascade Falls”
- Spring Grove Dwarf Gingko
- 30-40 feet with great fall color
- Henry Hicks Sweetbay Magnolia
- Northern Belle Magnolia
- Saucer Magnolia
- “Lavender Twist”
- “Appalachian Red”
- “Ruby Falls”
- “Hearts of Gold”
- “Rising Sun”
- aka Seven-Sons Flower
- Ugly at nursery but tough and rejuvinable
- Pollinators LOVE it and late summer to fall bloom makes for good food timing
- Some native
- “Willow Leaf”
- Shrub-sized evergreen option, tan winter color
- “Poor man’s rhododendron”
- Flower ok but great foliage
- Tolerant of abuse, rejuvinable