For those of us with small landscapes, dwarf cultivars of native plants can seem like a gift from heaven. Want to grow a particular native plant, but just don’t have the room? Have a straight species plant, like a native viburnum, that needs a pollinator partner for fruit production – but you just can’t squeeze another large viburnum in your landscape? Dwarf cultivars seem to satisfy that plant need, and for many of us – that plant lust – when we want a certain plant that we just can’t have.
But, do dwarf nativars really measure up? Maybe a version of the following story has happened to you:
You’ve planted a lovely American cranberry bush (Viburnum opulus var. americanum, formerly known as Viburnum trilobum). In May, the flowers appear, but year after year there is little to no fruit on the plant. But wait, you heard that this plant is self-fertile. After reading an EcoBeneficial blog post (the smart gardener that you are) you learn that this plant needs a genetically different partner of the same species for best cross-pollination and fruit development.
The problem is that you just don’t have enough room in your landscape for another really large shrub.
While you are plant shopping one day, you come across the answer to your lonely viburnum’s prayers – a dwarf American cranberry bush with the plant tag Viburnum trilobum ‘Bailey Compact.’ You scoop it up, pleased that you solved this plant problem. Now, you will see glorious, abundant fruit and the overwintering birds in your landscape will have more winter food.
Not so fast, native gardener. You have been duped!
Consider this listing from an online nursery, selling the dwarf Viburnum trilobum ‘Bailey Compact’: “An excellent compact, rounded form of American cranberry growing 5-6′ tall and wide. Flowers and fruit are typical of the species but are sparse and should not be the primary consideration for planting.”
Here’s another online “sales pitch” for this particular nativar: “Does not flower or fruit at a young age and only lightly thereafter.”
And, this illuminating info from the Chicago Botanic Garden website: “The white flowers in May and the red fruits are only sparsely produced.”
I’m sorry, but what native gardener, or any gardener for that matter, wants an American cranberry bush that doesn’t produce plenty of flowers and fruit? Like its straight species plant counterpart, this dwarf viburnum may serve as a larval host plant to a number of moth species, and it does photosynthesize. But is that enough? Let me answer that question, from an ecological perspective – “NO!”
Plant breeders frequently produce plants that lack robust ecological functioning. In the case above, that plant may look like a native viburnum, but it certainly doesn’t function like one.
Don’t get me wrong – some nativars are really ecologically-useful plants. Some are not. Physocarpos opulifolius ‘Nana’ (Common Ninebark) is a fantastic dwarf cultivar that has the form, color and function of the straight species plant, but in a smaller package. Do your research and let growers, nurseries and garden centers know what you and nature really need.
Just say “no” to those dwarf nativars that are one step away from being plastic plants.
Happy gardening from Kim Eierman at EcoBeneficial!
Photo: Viburnum trilobum ‘Bailey Compact’ – a dwarf nativar without the eco-juice.