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What's Blooming in July: Greenroof Shelter

Newly replanted Green Roof Shelter in Children's Garden

What's Blooming in July: Greenroof Shelter

by Josh Cornell, Horticulturist, The Gardens on Spring Creek 

During the summer of 2019, the Green Roof Shelter in the Children’s Garden underwent a much-needed renovation. With new waterproof underlayment, as well as a new soil retention system and redesigned irrigation, it was all set for a new plant palate. A garden space mimicking the ecosystem of a shortgrass prairie is replacing the sedums that had taken over from the previous planting. These plants often deal with the some of the same challenges in their natural settings as they will on the green roof – including shallow soil depth and fluctuating seasonal extremes in temperature.

Blue gramma (Bouteloua gracilis)

Based on a shortgrass prairie, one would obviously expect to see...grasses. On our green roof you will find blue gramma (Bouteloua gracilis), sideoats gramma (Bouteloua curtipendula), sand dropseed (Sporobolus cryptandrus), blue fescue (Festuca ‘Boulder Blue’) as well as  some annual rye (Lolium multiflorum) was used to stabilize the media last winter. Most noticeable are the seed heads of the blue gramma, which resemble little “eyebrows” or “eyelashes”.

California poppies (Eschscholzia californica)

Along with the grasses there are also a selection of blooming plants to add splashes of color. A few of the standouts are California poppies (Eschscholzia californica), Western wallflower (Erysimum capitatum), Hartweg evening primrose (Calylophus hartwegii), sacred thornapple (Datura wrightii), along with several varieties of Penstemon, Agastache, Echinacea and Artemisia. The intense scarlet blooms of the Humboldt County fuchsia (Epilobium septentrionale ‘Waynes Silver’) and hummingbird trumpet mint (Monardella macrantha ‘Marian Sampson’) planted around the edges are a favorite of the hummingbirds and will be sure to catch your eye. Some pasque flowers (Pulsatilla vulgaris ‘Rote Glocke’ and ‘Blau Glocke’) are also thrown in to bring some color, and hope, in early spring.

A collection of unique cold hardy cacti have also been added to the green roof. This idea came about after reading an article about sod roof houses in Nebraska, built by the pioneers. The accompanying pictures revealed beavertail cactus (Opuntia sp.) growing on these old rooves. I felt they add a beauty and texture appropriate for our western landscape. Several species of Opuntia with unique bloom colors and winter pad coloring have been added. With blooms varying from white and cream to citrus shades of orange and yellow, they will be a sight not to miss. Also planted is one of my favorites, the claret cup cactus (Echinocereus triglochidiatus). Its large, red blooms draw the attention of pollinators and people alike.

It has been a satisfying endeavor to watch the green roof garden evolve from total rebuild, reseeding and replanting, to its emergence this summer. It changes every week with more blooms and will continue to evolve and mature with the passing years. I look forward to seeing its changes and growth through the years, and I hope you will too!