One of my favorite gardens is not a garden at all, though it has been under the careful attention of humans for over 5000 years. The Glacial Heritage Preserve is 120 of the remaining 3000 acres of Pacific Northwest prairies, which once spread across over 300,000 acres. These prairies are the most endangered ecosystem in the U.S.

They are not only ecological and culturally important they are also shamelessly beautiful:

These mixed grasslands are quite different form the tall grass prairies of the interior of the continent. The grasses are actually quite short, evergreen and drought tolerant. These prairies don’t enjoy the heavy deep rains of the Midwest summers. Actually during the height of the growing season we see the least amount of rain here.

Roemer’ fescue (Festuca roemeri)

Luzula sp.

These low growing grasslands can host upwards of 700 species of plants in a healthy condition. Unfortunately since the 1850s and the arrival of Europeans these prairies have either vanished or degraded excessively. This was the only open ground in the heavily forested Northwest, and European settles saw it like parkland and the perfect place to start a farm. Tilling and repression of fires, quickly eradicated many native plants. The indigenous tribes who had lived in this area for nearly 10,000 years had actually been “ farming” these fields, primarily for quamash— a member of the lily family with a starchy edible bulb.

Quamash, or camas (Camassia quamash)

There are still many botanical jewels in these prairies, which are receiving a different sort of human attention these days.

Small-flowered Blue-eyed Mary (Collinsia parviflora)

Death camas  ( Zygadenus venosus var. venosus)

Sea Blush (Plectritis congesta)

Chocolate lily (Fritillaria affinis)

Blue Toadflax (Nuttallanthus canadensis)

Wild Strawberry ( Fragaria virginiana var platypetala)

Golden Paintbrush ( Castilleja levisecta) in a bed of sea blush.

Botanist, ecologists and zoologists and many volunteers are working to bring these delicate ecosystems back to a former glory. Burning has returned and much weeding. One of the major problem of the prairies is the encroachment of non-native plants which crowd out the natives. The biggest culprit is scotch broom (Cytisus scoparius).

What arrived as a 3 seeds back in the late 1800s has become a menace. One can hardly blame the Scottish ship captain Walter Grant for the part he played. He wanted to grow a familiar plant from his homeland. But no one at that time knew how at home scotch broom would get in the Pacific Northwest, so they planted it for erosion control after they clear cut the forests. Even into the 1960s scotch broom was being planted after freeway construction to control erosion. Well, the seeds of those plants—they can remain viable for up to 80 years— have spread from one end of the western parts of state to the other. Though you can see them almost anywhere, they are most prevalent in the gravelly outwash soils south of Puget Sound, the same soils that are home to our rare prairies.

Brooms rightfully have a bad reputation in the Northwest, though their gaudy gold is as much a sign of high spring in the Northwest as rhododendrons. I have planted brooms in clients gardens; I even grow two in my own. But I have carefully selected cultivars that are sterile, or species that are too cold sensitive to seed in and become a nuisance. I am vigilante in my watch for any seedlings, and have been happily rewarded with none to date.

Cytisus dallimorei ‘Lena’ ( A sterile Royal Horticultural Society Award of Merit winner)

Cytisus alba ‘Elegantissima’

I also grow the Spanish broom (Spartium junceum) in a pot. I was sure it would never make it through the winter here, but it has survived three winter with minimal protection. This year I’ll plant it in the ground. Of all the brooms this one has the most delicious fragrance easily compared to pineapple.

When I was in Prescott, Arizona this winter, my friends told me that Spanish broom seeds around quite vigorously there; this is on a mile-high plateau far from any maritime climatic influences. It made me wonder about my brooms. Those “garden friendly” one.

And I ‘m starting to wonder if making room for brooms might be a mistake. Especially when I can have this…

And this…

And this…