Ruthless gardening

Sunday, 16 May 2010

A chrysanthemum that is too floppy and has gone berserk: for the axe!

One of my favourite gardening writers, Vita Sackville-West, of Sissingurst fame, once wrote that the only way to garden is to be ruthless: 'The true gardener must be brutal, and imaginative for the future'. I think this time of year is a good one for evaluating your garden and deciding which plants you have may not be worthwhile keeping. It pays to be a bit hard-hearted about this process and to remember that every plant that is pulled out will give you space to put in a new one. This is relevant to me, as I have easily a hundred plants in pots waiting for homes!

There are no ironclad rules for how to decide if a plant should stay or go, but in walking around my garden this week, I came up with a few pointers that might help indicate where the axe should fall.

Phygelius cultivar that has gone berserk

Plants that go berserk: this category includes creepers that cover everything in sight, perennials with vigorous, questing roots that want to take over whole garden beds, shrubs which grow too wide or trees that grow far too tall for a normal suburban backyard. Though I often have reassured myself as I plant one of these monsters, that of course I will keep it under control by judicious pruning or digging out unwanted bits that have wandered too far, the sad fact is that I often don't get around to it. These plants cause a lot of work, can smother other plants, and if left in the ground for too long, are almost impossible to get rid of. Be suspicious when someone wants to offer you a plant that 'grows really easily'. In our early, unconfident gardening days, this may seem like a positive attribute - but as we get more experience, we realise it is not! In my own garden, I am about to remove a lovely dusky red Phygelius cultivar, because what I fondly imagined to be a small and sedate shrubby perennial, has taken over at least a square metre of a garden bed, muscling out smaller, more fragile treasures.

Dahlia Timothy Hammett is a poorly shaped plant

Plants with poor form: although flowers are usually what attract us to a plant, we have to remind ourselves that they are transient, whereas the overall shape of the plant is there all year round. Although it is OK to have a modicum of plants that form an amorphous mass, if there are nothing but these, a garden is in danger of resembling nothing more than a collection of blobs. And if the plants are all herbaceous perennials, you are left with nothing at all in winter when they die down to become dormant. I like plants with a strong natural shape, but also enjoy clipped hedges and topiarised shapes to give structure to a garden. Sometimes poor form can be linked with a need for staking, and that also annoys me. I am about to remove the hybrid tree Dahlia 'Timothy Hammett' because it has no shape and is always falling over. Supposed to be a metre tall, it has grown to 3m and has no strength to holds itself up. It also leaves an ugly gap when it is cut back to the ground after flowering. Out it goes!

Plants that are out of their comfort zone: I know that many gardeners do enjoy the challenge of being able to grow cold-climate or truly tropical plants in Sydney and who am I to deny them that pleasure? There is a certain frisson in knowing you are probably one of the few people to be able to grow a lily-of-the-valley or a Heliconia in Sydney, but realistically, they will never look as happy as they would be in their preferred climate. These days I don't have time to spend cosseting such plants and find it hard to believe I once used to put ice cubes around plants that wanted a colder winter than ours! My earliest gardening efforts were based on English gardening books, and resulted in many failures because I was trying to grow plants suited to a climate totally unlike my own. When I discovered the wealth of plants from Central and South America, South Africa, Mexico and other warm lands that flourish in Sydney, I realised that we could create our own style of gardens that can look every bit as good as a lush English perennial border. And gardeners in cold climates envy us for what we can grow!

Melianthus major has beautiful leaves

Plants with boring leaves: there are so many plants with lovely leaves that it seems a shame to grow any that have spitefully dull ones. Look for plants with beautifully shaped leaves, unusually coloured ones or those with wonderful tactile texture. Leaves are with us for far longer than flowers, so foliage should be a prime consideration when choosing a plant. It is worthwhile going round your garden and looking critically at the leaves of all your plants to see what contribution they are making to the scene.

Abutlion leaves are subject to attack by the leaf-rolling caterpillar

Plants that are vulnerable to pest attack: as I don't like spraying pesticides, I don't have a lot of patience with plants that are prone to particular pests, which is why I gave up growing azaleas. I am almost over Abutilon for the same reason - though I have loved this genus for many years, this year the attack of the dreaded leaf-rolling caterpillars so decimated my specimens that I am on the verge of removing them. I am going to give them one last chance, using eco-friendly white oil as a spray next summer but they are definitely on notice!

Salvia blepharophylla did not thrive in my garden so will be removed

Plants that look too much the same as other plants: this is a tricky one, because those of us with a passion for a particular genus of plants find ourselves adding to our collections, perhaps beyond the point of it being aesthetically pleasing. In fact, dare I say, the garden may start looking like a monoculture, and one of the rules of gardening that seems to be important is to have variety in shape and texture to give a satisfying look. In my own case, I have more than enough specimens of Salvia now and I have to start being very selective in adding any more. I am using some of the criteria outlines above to make this decision: ones that grow far too vigorously, have a poor shape or which are not thriving well are going to get the chop. With so many beautiful Salvia to pick from, we really can afford to be choosy and to pick the most attractive and well-behaved specimens to adorn our gardens.

As well as getting rid of substandard plants, this is a good time of year to move plants that are in the wrong position. As gardeners we always look towards the future to improve our gardens and live with the hope that next year, it will all look soooo much better!