PLANT OF THE MONTH

Three-toothed Cinquefoil is not a very common plant. It has only recently been renamed to Sibbaldiopsis tridentate owing to systemic phylogenetic work that places it closer to Sibbaldia genus.

JIM FUNAI, LIC Cuyahoga Community College SHELLEY FUNAI, LIC Stan Hywet Hall and Gardens

Potentilla – as a genus name – is usually associated with P. fruticose, the shrubby Cinquefoil that comes in an insane number of cultivars. And, while P. fruticosa has been stealing the spotlight for some time within the genus, a potential contender was removed all together, without many of us even realizing it. Officially, Potentilla tridentata ‘Nuuk’ has had its name changed to Sibbaldiopsis tridentate. Wait... does that mean we just put the wrong name in the title of our article? Let us explain.

First, keep in mind that our nurseries are in a constant dance with plant names changing. If they were to immediately jump on every name change, many clients might think they were simply sold out of the plant they want. Thus, we had a feeling if we led with Sibbaldiopsis tridentate, many of you might have skipped the article thinking we lost our minds. You certainly wouldn’t find THAT plant in any local nurseries, right? Second, we plant nerds can be a bit stubborn with name changes. We, like many of you, resist some of these changes because they don’t make sense to our eyes.

That said, now that taxonomists have started sorting plants by DNA traits, they’ve been moving some plants around that don’t make sense based on their appearance alone. There is logic in organizing plants this way, as it gives us a better understanding continued on page 22

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of how these plants will react to a rapidly changing climate, and foreign pests and disease attacks, which are on the rise because of international trade and travel.

While there is no official record of Sibbaldiopsis tridentata in Ohio, there is for nearly every state surrounding us, especially when traveling south in higher elevations of the Appalachian Mountains. The plant can be found into the far reaches of the Canadian tundra and into the steep slopes of Greenland. It is likely the species exists in a native habitat here in Ohio, especially somewhere in the Appalachia region of the state.

A species called Sibbaldia procumbens (Creeping Sibbaldia) is what our plant of the month is more closely related to, rather than the Potentillas, As such, the name for our plant had the “opsis” (Latin: similar to) thrown on the end indicating it is similar to Sibbaldia. Sibbaldiopsis remains in the Roseaceae family, which is clear in the characteristic flower; 5 white petals and prominent stamens. These bright-white flowers put on a show from June thru August, yet don’t give way to an ornamental fruit. Considering the native habitats within which this plant is found – including grassy balds in the southern range of the Appalachians, tundra in the north and steep rocky slopes through Nova Scotia into Greenland – this plant is one for the rock garden. Coming in at a grandiose 6 to 10 inches tall, this little guy will slowly spread up to 18 inches in width (so plant them tight). Think of it as a unique ground cover for the native garden.

The leaves are palmately compound, splitting into 3 leaflets. Color is a deep, glossy-green with exactly three teeth at the tip of each leaflet. Having the look of an Alpine plant, the leaves arch out from the base on very short stems. In full sun – which is preferred – some of the leaves will turn a bright red, adding to the ornamental offerings of the plant. Most people would think this plant is an herbaceous perennial, but it maintains woody stems above ground, year-round, and is often evergreen in our region.

This plant is extremely hardy, laughing at a zone 3 winter (-40 F), but is a bit more sensitive to high heat and humidity. It will certainly die in heavy, wet soils. In fact, the trick

with this specialty, rock garden-type plant is creating the ideal soil. While sand will help with drainage, it is useless for holding available water in the dry months. We would suggest incorporating a lightweight, expanded shale, slate, or clay (think of “bonsai soil”) to help improve drainage while holding available moisture for the plants.

In building a rock garden, the key is naturalistic placement of large boulders, ideally with lichens already covering the surfaces. Work your way down to smaller cobbles and some large gravel, filling the voids between the larger rocks with plant material. Use your planting mix to create the pockets for these plants.

As mentioned, the planting mix will perform best with expanded shale, or similar material, mixed with well composted organics at a ratio of around 4:1. As you place the planting soil, use a hose to really soak it, which will help to fill the voids within the mix. Remember, if you use only sand and some organics, your soil will not hold the needed moisture levels to keep these plants rocking through the summer. Your finished product will be a garden that mimics the rocky outcrops of the Appalachian mountain range and the steep rocky slopes of Nova Scotia.

Finally, here’s one last piece of trivia before we leave you this month. Sibbaldiopsis tridentata ‘Nuuk’ is named after the capital city of Greenland, Nuuk. It was selected for its dense grouping of leaves and is listed as an endangered plant in most states due to habitat destruction and global climate change. It is a specialty pollinator which hosts several native bees, as well as many butterfly species.

While we’re aware this may not be the next plant to solve all your landscape issues, perhaps you have a client that would jump at the opportunity for a specialty garden. Think of how fun it could be to research and bring to life!

Jim Funai, PhD., is full-time faculty at Cuyahoga Community College, a NALP accredited associate of applied science in hoticulture degree program. He has a PhD in Landscape Engineering and Forestry and is a Licensed Arborist. Shelley Funai is Grounds Manager at Stan Hywett Hall and Gardens in Akron, Ohio, which offers a historic estate designed by Warren H. Manning and a beautiful manor house museum. She is Landscape Industry Certified in Ornamental Plant Care.