Gone Gardening – Bolster your garden with something big and bold

Hey there, time traveller!
This article was published 16/08/2012 (4894 days ago), so information in it may no longer be current.

Big, bold, and beautiful! You will think that I am obsessed with everything over-sized as I wrote about large hanging baskets not that long ago and here I am again singing the praises of all things big.

This week I will discuss large plants in the landscape: which large plants are best suited to our area, how they can be used in your garden, and some of the particular maintenance issues you might face when growing some of these giants. Many large plants are no more difficult to grow than the smaller plants to which we are more accustomed.

In my garden, the most obvious large plants are the cannas, which I grow in the back patio area in full sun. I grow several in large pots on the steps leading up to the garden doors and the rest I plant in a raised bed along the foundation of the house.

By the third week of July, they were in full bloom and at their peak although they will produce more blooming spikes as the summer turns into fall. I give them a head start by planting them early in peat moss and growing them in my cold frame. By the time I plant them out in mid-May, they are usually about 30-40 centimetres high.

Cannas give a tropical touch to the landscape and their brilliantly coloured blooms also are quite exotic — I have the regular scarlet ones as well as some bright orange and some golden-apricot ones. I also have a few with interesting striped foliage.

Cannas are useful as container plants but they also can be planted in the ground. They require ample amounts of water but otherwise they are easy to care for — although they do not like hail, as the tattered lower leaves on some of mine illustrate!

The castor bean is another large plant that has exotic, tropical looking foliage. Its leaves are like huge maple leaves with a tinge of burgundy.

The bright orange seed pods are quite striking, and although they are said to be poisonous, I don’t intend to eat them and the prickly nature of the seed pods I’m sure will easily deter anyone else from even touching them.

Both cannas and castor beans are useful as backdrop plants in a large flower border, as foundation plants, and also as specimen plants — I have one caster bean plant this year in a large pot on the front driveway. The plant has enough visual interest to stand on its own, although I do have a bit of variegated plectranthus (Swedish ivy) planted at its base.

I bought my castor bean at a greenhouse but they can be started from seed in the house. They must be given an early start indoors if they are to reach any kind of size in the outdoor garden. By mid-July my castor bean was a little over a metre high.

At the back of one of my perennial beds I have two large plants; one is just going out of bloom by early August while the other is just coming into bloom. Both are old, reliable perennials that are very easy to grow.

The first, valeriana, produces fragrant white blooms atop its two-metre-plus stems and scents the garden for about two months beginning in early June. It is a rather rugged looking plant, so I have it at the back of the border — which is the perfect place for it because of its height.

The plant just coming into bloom is golden glow, which is a rudbeckia that produces double golden blooms for about six weeks starting in early August. It is a great cut flower and provides a splash of gold in the autumn garden just when many other perennials have bloomed themselves out.

Another large perennial that I admire in other people’s gardens but do not grow myself is plume poppy. I am limited in the number of large plants that I can grow by the small size of my garden.

I like the coppery tint to the large leaves, which are nicely scalloped, and by its upright growth habit. It has frothy blooms not unlike those of filipendula, except they are more white than pink.

The blooms gradually turn an attractive buff colour as they go past, and many people clip off the spent blooms as this plant does have a reputation — like many poppies — for excessive self-seeding. The foliage is its main attraction.

My huge rhubarb plant is situated in the vegetable garden but is very visible from the lawn and grows in front of the two aforementioned plants. It too is a great architectural plant and provides attractive foliage all summer long.

Large plants add substance to the garden, serve as background or as foundation plantings, screen unsightly views, add architectural elements to the landscape, lend a vertical dimension to plantings, and can provide an exotic touch to a garden room.

For the rest of the summer, observe carefully how fellow gardeners have used large plants in their landscapes to give you some ideas for using these big beauties in your own landscape next year.