A few weeks ago I had the privilege of traveling to Madison, Wisconsin to speak to the Wisconsin Hardy Plant Society. My friend Jeff Epping offered to show me around the day of the presentation. If you don't know Jeff, he is the retired director of Horticulture from Olbrich Botanical Gardens. He has risen to prominence for his design work with gravel gardens, and really he is one of the foremost experts on this approach to planting in the US.
Gravel gardening has gained interest in recent years due to the desire to have a beautiful naturalistic garden with limited maintenance due to reduced weed pressure. The upfront costs are more expensive, but corporations, cities, and campuses can actually save money in the long run with these planting approaches.
Ultimately a layer of gravel—preferably an angular gravel—is put on top of the soil, and then plants are planted into that. Because the gravel layer introduces stress against competitors, more species are usually able to be planted in a gravel garden and survive over time. I should also clarify that gravel gardens are not the same as the rock mulch you see in gas stations and fast food restaurants.
Jeff took me to see a newly planted gravel garden at the Madison Parks Lakeside Offices that was just installed in the summer of 2024, and one at Olbrich Botanical Gardens that was planted in 2014. I think it’s helpful to see photos of a fresh planting and one that has had time to mature, so enjoy the comparison photos below.
Madison Parks Lakeside Offices
Jeff noted that while space between the grit was visible now, it would fill in.
Eryngium yuccifolium (rattlesnake master) and Liatris ligulistylis (northern blazingstar) are a good emergent layer for the gravel garden.
Even this little strip next to the parking lot featured a gravel garden planting.
Dalea purpurea (purple prairie clover) was in bloom in the garden.
A dried Allium (wild onion) umbel offers late season interest.
I noted how richly colored the Bouteloua curtipendula (side-oats grama) were in the gravel garden. I love their safety cone orange-colored stamens.
A close-up of the grit that Jeff uses. It's a quartzite material and doesn't decompose and has limited fines to reduce weed growth.
Jeff commented how they didn't want the whole area to be a gravel garden. So, they did a Sporobolus heterolepis (prairie dropseed) meadow.
Sporobolus catches the early light. I noted how much taller and lusher prairie dropseed is in Wisconsin than in Texas.
Sporobolus heterolepis (prairie dropseed) glimmers in the morning light.
The Entrance Gravel Garden at Olbrich Botanical Gardens
This gravel garden is over ten years old and features a healthy mix of herbaceous plants. Silphium terebinthinaceum (prairie dock) was such a prominent species in the gravel garden with its bold foliage and tall inflorescences.
Liatris ligulistylis (northern blazingstar) blooms among other gravel garden companions.
A painted sign shares how wonderful Silphium terebinthinaceum (prairie dock) is as a plant.
Euphorbia corollata (flowering spurge) is a dynamic filler for late summer and early fall color.
A bee hotel provides nesting habitat and an educational opportunity for visitors.
Liatris ligulistylis (northern blazingstar) pops out of the gravel garden.
The effervescence of Calamintha (calamint) is a foil for the seedheads of Echinacea (purple coneflower).
A distance shot of the gravel garden gives an overview of the growth habit of many perennials.
If you want to learn more about gravel gardens, my next post in two weeks will feature another planting Jeff installed at Epic Campus. Stay tuned!