Spikes and spires of hardy perennials add a structural aspect to the landscape.
These plants are must-haves for any perennial border because they can be used as specimen plants, add a vertical dimension to a flower border and put on a good display of bloom behind shorter plants in the border.
Hostas produce lovely spikes of purple, lavender and white that add beauty to the shade garden. The colours are so peaceful and soothing that they belong in the tranquil setting of the shade garden. Their cool colours are in sharp contrast to ligularia, the Rocket, another perennial blooming in the shade at this time of year.
The deep golden spikes of ligulara can be almost two metres tall. My ligularia was once in a semi-shaded location, but it would wilt when the sun struck it.
In full shade, it never wilts and produces long-lasting spikes of pure gold. Alongside the ligularia are two clumps of monkshood, which produce tall spikes of dark purple bloom, a nice contrast to the golden ligularia.
There is a bi-coloured blue and white variety but I prefer the dark purple one because it is a narrower plant with a more upright growth habit. I have found that monkshood is happier in full shade where foliage doesn’t dry up in the heat of late summer.
The prime lupine season has passed, but because I depend upon a self-seeded patch that is adjacent to the shade garden and in part shade, my lupines are usually late to bloom. Also, some of the new seedlings bloom in the fall, instead of early summer.
Nothing can beat the beauty of lupines in full bloom. They come in such a wide variety of colours, ranging from the deepest reds to salmon and pink to shades of purple and lavender.
They like lots of moisture and can be temperamental. I find that once you find a spot where they are happy, they will dependably bloom year after year.
Among plants that are grown in full sun, perennial veronica is a hardy and dependable plant with a long bloom period. Its purple spikes will last for several weeks and many spikes will still show some colour when fall frosts arrive.
I have the compact variety, Sunny Border Blue, and I really like its dark green foliage and tidy growth habit. It does not grow as tall as many of the veronicas so it doesn’t sprawl or require supports.
I also like the taller varieties for the back of the border.
These plants can be staked without supports being obtrusive, and their tall purple spikes create an attractive background to the shorter plants in front.
Purple sage, a close relative of veronica, is also an attractive perennial. It can be positioned at the back of a border but it also makes a great specimen plant be-cause of its substance and size.
The best display of delphiniums occurs in July, but if you grow seedlings, many of them will put forth spikes of bloom in August or September. Delphiniums will self-seed profusely if not deadheaded.
While these seedling spikes will not be as big and spectacular as those produced earlier in the year by mature plants, they are attractive in the fall garden.
Perennial spikes would be complete without verbascum. These tough, drought resistant plants are easy care and extremely hardy.
The clumps of V. Chaixii Album with their tall spires of white blooms with plum-pink eyes often have butterflies or hummingbirds hovering nearby along with the yellow spires of Arctic Summer.
Verbascum spikes are unusual because there are open flowers here and there all along the length of the spikes instead of having flowers opening up sequentially from the bottom to the top.
Other perennials that produce spikes and spires of bloom in-clude liatrus, which blooms in early summer, and can be mauve-purple or white. Liatrus has an unusual characteristic, with flowers opening up from the top of the spike down.
Another perennial with good spikes of bloom is culver’s root veronicastrum. It produces snake-like white spikes in mid-summer with a crook in them that gives them the shape of a swan’s neck.