Rock Gardening - great winter project

Steve Marak

Steve Marak’s opening comment in his talk about rock gardens was, “Rock gardening is not a pot full of rocks, even though that would live no matter what.” 

Marak recently spoke about rock gardening at the Flower, Garden and Nature Society of NW Arkansas, a club he helped found. 

Alpine gardening, which is a garden filled with plants that grow in Alpine mountain regions, includes a) crevice or deep excavation, and b)rock face or dry-stacked gardens.

A rock garden is usually filled with small and low-to-the-ground plants that bloom all at once with flowers that are large relative to the size of the plant clump.

In order to grow rock garden plants in our high-rainfall area we must try to replicate their native environment by bringing in a large quantity of mixed-sized rocks. The most efficient way to create a rock garden is with a load of scree piled on a slope.

Marak said, “Scree’s mixture of rock sizes provides sharp drainage to oxygenate the water, shelter rock garden plants’ deep and sometimes trailing roots and hold heat to protect roots from changing soil temperatures. The rocks are fundamental not just ornamental.”

The rock garden you build needs no fertilizer, no soil, and, can be completely filled with native plants. The rocks are easy to collect into a pile and builder’s sand (not play sand) is the ideal filler.  

To start a new garden, pile the scree 3 or 4 feet high with a slope on one side for drainage and to display the planting arrangement. Landscape border stones can be stacked at the high side to hold the scree pile in place.

“Native plants are what I recommend,” said Marak. “They are easy and adapted. Literally there are thousands of plants that could work.”

The plants will have to be watered to settle them in, and until they become established, plus the summers when there is a drought.  Otherwise the plants will do well without supplemental water.

“I recommend native plants for local rock gardens,” Marak said. “They are easy to find at local garden centers.”

The plants he suggests include: Poppies, dwarf conifers, succulents, cacti, sedums (King’s Crown), Bird’s Foot Violet, Goat’s Rue, Purple Prairie Clover, Thyme, small Asters, Verbena, Penstemon, perennial Candy Tuft (Iberis Sempervirens), Claytonia, moss Campion, Missouri Evening Primrose, Senecio, and daylilies.

Containers can be planted and placed along the outer border of your rock garden. Sedum plants could be planted into hypertufa containers (www.hypertufa.net).

Marak said, “Hellstrips – those areas between the sidewalk and the street where nothing else will grow – can be ideal locations for rock gardens.”

Seed starting

Salvia seeds – Fill a berry box with potting soil that drains well and wet it. When the soil is drained, place the seeds on top of the moist soil and mist them to make the stick or settle. Put the container outside for the winter, cover with plastic wrap and water from the bottom when needed.  Transplant the seedlings into individual containers when they have 4 leaves.

Penstemon seeds have a germination-inhibitor coating so cold and dry alternated with moisture is replicated outdoors over the winter.  Add perlite, vermiculite or builders sand to potting mix. Moisten, surface sow the seeds and moisten the top with a sprayer. Cover the container with clear plastic or glass. Place outside and water from the bottom as needed.

Plant ideas and seed starting
Alpines www.alpinegardensociety.net/
Canada  www.onrockgarden.com/
North America NARGS www.nargs.org
Oklahoma natives  www.oknativeplants.org/
Scottish Rock Garden Society www.srgc.net
Tulsa Cacti and Succulent Society http://hort.li/1CQ0, jwkeeth@gmail.com and 918.321.3133

Seeds and plants
Alpine Seeds www.alpine-seeds.com
Easy Wildflowers http://easywildflowers.com
High Country www.highcountrygardens.com
Jelitto Seed http://jelitto.com
Native American Seed www.seedsource.com/
Outside Pride www.outsidepride.com
Swallowtail www.swallowtailgardenseeds.com/