Yellow Signals Spring
If you have these easy-to-grow plants in your troughs, you can expect blooms in late March and early April in Zone 3.
Draba mollissima, an evergreen, can take temperatures a few degrees below zero. It’s evergreen and starts to set it’s bright yellow flowers in March in Calgary. Draba mollissima grows slowly and may eventually reach 10 cm high, mine is about half that size.
The trough does get lightly watered throughout the winter, depending on the weather, with special attention paid when the warm Chinook winds are blowing. But you have to be careful, because the plant is not actively growing – think about a windswept, dry, mountaintop growing environment – that’s what I’m trying to replicate 11 floors up on the balcony during the winter months.
I bought Saxifraga ferdinandi coburgi because of it’s foliage – it has soft, woolly, grey-green leaves. So it’s strikingly different from the other saxifrage in my troughs, which typically have glossy, bright or dark green foliage. This plant is another evergreen. It grows, like many saxifrage in a cushion form. But look at the flowers. Tiny, bright yellow and completely covering the surface of the plant. This one wintered over in the trough without a problem, again, lightly watered throughout the cold season. When mature it should top out in size and be about 10 cm high and wide.
Both of these plants have to be planted in a well-drained soil and need some sun. They have both been mulched with forestry grit in order to help retain moisture in the soil. And knock on wood, they both seem to be generally disease-free.
Troughs and Tiny Textures
Alpine plants in hypertufa troughs make up part of my balcony plantings. The selection of plants in each trough is based on texture, colour and form. Many of these plants are tough, and seem not to mind the growing environment on the balcony. About 30 to 40 per cent will winter-over.
Hypertufa is a man-made material used to make containers that resemble old stone troughs. The troughs are made with a mixture of Portland cement, peat moss, builder’s sand and water in equal amounts, molded over a form and cured. Hypertufa seems to be frost resistant.
The troughs are watered daily and are in full sun. Many of the alpine plants have brief, brilliant blooms and then bulk up throughout the summer. Some self-seed. A cool dry spring does not prevent the alpines from sprouting and starting their early display of flowers. Many of the flowers are yellow or blue. A spectacular lavender blue dwarf arctic iris pictured below is a native of Alaska.
Tiny evergreen Draba aizoides, pictured below is often up and flowering in mid-March on my balcony. The narrow, pointed, bristly leaves form small mounds, and its bright yellow flowers have 4 petals. The leaf mounds are about 2.5 cm high and the tiny individual flowers form in clusters which are about 2 cm in diameter. This is a hardy performer and survives to -36°C.
Draba aizoides likes full sun, needs to be in well drained, gritty soil in a trough and is drought tolerant. Clumps may have s single taproot, but side rosettes may also set small roots which can develop into their own taproots. This plant is native to the European mountains.
The miniature dwarf bearded iris pictured below beside the draba grows to 16.5 cm and produces a 6.5 cm bright yellow flower. The plants will to over-winter in the troughs – doubling their spread each year.
Inspiration for the hypertufa troughs comes from weekend hikes and holidays in the Rocky Mountains. I’m only one or two CDs away from some of the best hiking trails in Canada. On Parker Ridge in July each year you can see Rock Jasmine with its creamy white flowers with yellow, orange or pinkish eyes at the centre. It is sweet-scented.
Yellow mountain saxifrage with it’s tiny yellow flowers is at the top of the hike. These plants are huddled up tight against the wind swept rocks in mat and cushion form. Flower has 5 long, narrow petals with 10 stamens.
White Dryad or Mountain Avens are easy to see along the trail to the top. They have white flowers with yellow stamens and grow in low mats of textured, leathery, scallop edge leaves.
A little further down the road you can see more yellow alpines on the Wilcox Pass trail. this yellow draba has soft green foliage and is a low-growing tufted plant. Golden fleabane blooms in July with a bright yellow flower head which often appears too large for the plant. It’s common on alpine slopes. And yellow columbine flowers on a slender stem.
The large trough at top has been planted with a Saxifraga called Purple Robe, nice dark burgundy-purple flowers. Primula Juliana is tucked in the next corner and a locally grown Columbine, which flowers purple-blue has self seeded and taken on a good portion of the trough. Sweetly scented sedum and another saxifrage are also in the trough.
The Dwarf London Pride Saxifrage, pictured above in white flowers, is one of the easiest to grow in Zone 3. This plant can take some shade. It is drought tolerant once established and overwinters with no complaints in the tufa troughs. Dwarf London Pride forms dense rosettes of dark-green leathery leaves that slowly spread and form a thick mat. The rosette mounds grow to be about 10 cm high and the spread can be up to 20 cm. Tiny white, star-shaped flowers bloom in the late Spring if the plant is in the sun or bright shade – it may not flower in dense shade.
I only have so much room in the balcony garden. The Rununculus and primula, pictured above left, get a place in the troughs, but I head to Kananaskis to see the pretty pink Moss Campion. Its tiny, bright pink, 5-lobe, scented flowers grow on mounds of tight green foliage. Common harebell has a lilac, bell-shaped flower and toothed leaf. And although not an alpine, I often see the common wild rose at the base of many of my hikes. I like the soft pink shades of the 5-petal flower.