with “greenfingers” Malcolm Campbell
Malcolm W. Campbell is a sole trader ABN 48 639 428 626 © 2017
Perennials: Means work! by Malcolm Campbell
When I started to plan a cottage garden for my wife Annie, I needed to rely on lots
of colour and flowers early in the life of the garden so I had to rely on using annuals
in great drifts. However as the garden has matured the perennials have started to
assert themselves and it's now, that the real management dilemma of maintaining the
cottage garden is starting to sink in.
The term perennial is generally applied to non woody plants that live for more than two years, flower annually and most die down during a dormant season, that is usually our winter. The term perennial seems more widespread in Europe than in Australia because their dormancy falls in winter, when gardening is almost a no go activity anyhow. There are many of our native Australian plants that could be termed perennial, since they live more than two years and regularly die down in summer or during drought. Some are bulbs, orchids, perennial grasses, forbs, lichens, mosses and fungi, but we seldom think of them as perennials. In our gardens we think of spring and summer colour and lots of it.
Perennials mean work and lots of it. They are the gardeners' exercise machine. Perennials tend to get overplanted in any devotees garden, so be warned. You will also need to establish your compost heap, before you start a dedicated path to growing perennials. That's right. Compost! You see perennials create lots of foliage that needs removal. Call it pruning if you like, but for some it means a total number two crew-cut, down at the roots!
I grow Veronica spicata, the lovely blue flowering "Speedwell". In spring it rapidly grew from a tiny tubestock plant to a 1 metre high waving shrub, that sent all its branches out from a crowded base. At the end of every stem were long spikes of stunning blue flowers that flower for three or four weeks then set seed. I started removing the seed heads because they turned brown and didn't look to flash alongside the ever-present blue spikes of flower that just kept coming all summer and will into autumn. While I was away for a few weeks on my honeymoon, needless to saw the garden got overlooked, so when I returned I noticed that the seed heads were full of tiny black and red slug-looking larva. Well they had legs. Then they moulted yet again so that I instantly recognised them as 18 Spotted Lady birds and finally they emerged as the gorgeous little insect eaters that we love in our gardens. But in 30 years of gardening I'd overlooked this vital stage in the ladybirds' development. They had previously just flown into my garden, as mature little Ladybirds. The "Speedwell" was their breeding ground. Their whole life cycle in fact, so much so that I was very reluctant to cut that Veronica down in winter, but I did eventually in July when it was apparent that the ladybirds were all mature and no longer dependent on the waxy leaves of the "Speedwell". I still have lots of Ladybirds to clean up the Aphids on my Roses, but they've colonised other plants. They wouldn't normally bread in our winter anyhow, so I guess they'll be back this summer. The "Speedwell" in winter makes a small rosette of leaves at the base that take off rapidly in spring, with fresh new foliage and that is the appeal of perennials in a hot dry Mediterranean climate such as where I garden in Adelaide.
The chance to grow flowering plants that are not as water dependent in summer and yet still return a prolific flowering, is what is making perennials more popular in our southern gardens. I've noticed in English gardens perennials are generally grown in what they call 'a border'. Literally long thin beds, that either abut a lawn on large country estates or provide they only slice of garden in the typical long thin London backyard. Our perennial gardens need not be prescriptive. We usually have larger areas, not such severe winters as gardeners experience in Europe and we have room for a compost heap! Well most of us do.
When landscaping or setting the frame for a perennial garden, you will be aware that the cottage garden is the model. Little paths wandering everywhere and a general sense of controlled chaos. The paths provide access and I foolishly overlooked them when planning Annie's cottage garden that is rapidly filling with perennials. Ironically, I have paths where I never intended any, just because of the constant foot traffic to pick flowers or tip-prune and to weed of course. I'm finding that weeds are confined to areas that get less attention, such as near larger bushes. I'm not getting weeds amongst the annuals or anywhere near plants that get fertilised regularly, such as the Roses, Aquilegias, Dianthus, and Perennial Salvias. The weeds prefer to cluster around the tougher plants, that don't get fed very often, like the Lavenders, Pelargoniums, Wallflowers and Saponaria. I'm beginning to think I could fertilise weeds to death, since they didn't seem to want to compete against demanding, fast growing and long-flowering plants. I love it. Fertilise the weeds to death!
Before I get too excited I've noticed huge drifts of some of the annuals and some perennials that have self seeded in our garden, leaving less space for weeds anyhow. Our cottage garden is now such a dense landscape that the usual weeds probably cannot compete. Even the "Soursobs" Oxalis pes-capræ are now growing so lush and isolated that they make easy targets to pluck from the garden. It's when they grow tough and compact that they set so many pernicious bulbs, that come away from the stem as they are pulled from the garden. That's when they are real trouble. I've actually left a small bed of "Soursobs" in a long thin strip that runs down my driveway, because they keep the early Jonquils company in July-August and the combination looks lovely. I reckon I can contain them there and the succession in that bed is Spuria Iris in October-November, so they certainly have plenty of competition and from plants that don't get much attention or fertiliser. In summer I spell that bed totally. It dries off to set like concrete, with only the long dried flower heads of the Irises to provide interest. Still the Spuria, need that long dormancy, so that's the price to pay. They are perennials too, but summer dormant. I've got some lovely Amaryllis that will soon need a similar treatment and if you aim to grow Nerines or Brunsvigias, you'd be well advised to think of a combination that can be spelling in summer too, or else they loose their vigour in time and stop flowering if watered all summer. Some possibilities are to use winter-flowering annuals such as "Virginian Stock", Malcolmia in drifts. They form a prostrate drift that tiny tots cannot resist playing with, but fortunately they recover quickly!
One aspect of growing perennials that I find particularly annoying is that most of the reference books on perennials, assume we all garden on rich acidic soils and that we are only selecting our plants by height and spread. As though soil type was irrelevant. I garden on clay. Alkaline clay to boot and I've gone to no end of effort to improve drainage with gypsum being added quarterly first as a powder and since the garden has become more established, as a water soluble spray. When spraying I usually add some water soluble fertiliser, such as liquid Vitall®, which incidentally I can't read the N:P:K on the label as it's dissolved too. Sometimes I use the Thrive Easy Feed™ (N:P:K 27 : 5.5 : 9) or Aquasol™ (N:P:K 23 :4 : 18) if plants need a big potassium hit, to keep them interested in flowering. The fertilisers are used at the rate of two teaspoonfuls per four litres of liquid gypsum. That provides a mild foliar spray in a pretty low concentration, that is not going to burn the Gallardias and Zinnias. Both of which I've found are incredibly sensitive to water soluble fertiliser. I can only use organic pellets on them and even then, I've got to make sure they are not the enriched pellets! I have found that the fertiliser-shy perennials such as Dianthus, Perennial Zinnia and Gallardia can take the low N:P:K Kelp extracts, such as Maxicrop 100® and Natrakelp in their stride and not suffer leaf burn, when over sprayed. I have to admit that I use a lot of foliar sprays, at low concentration, but regularly, to offset nutrient deficiency that I have created in some areas of our cottage garden, by using a composted mulch up to 40cm thick. I've planted into this mulch and use it as a soil medium, since my natural soil is such heavy clay. The clay loving plants, like Roses are all planted around the edge where the mulch is thinnest and the plants that favour good drainage are all located on the mulch mounds. Most of the perennials like good drainage, so they are planted in the mulch. The details of this were in an article in this magazine called "Establishing my cottage garden" back in September last year.
While some folk plan their cottage garden around colour schemes, with a predominant theme, such as pink or yellow or even the non-colour white, it's usually been as a result of having visited the stunning Sissinghurst Castle garden in Britain. I accepted long ago, that having seen the white garden at Sissinghurst, I'd never bother to replicate it. No our garden is a riot of colour and form. I lean towards plants that grow in my climate and soil. I haven't sought to rigidly classify them as perennials or annuals, climbers, grasses or bulbs. If they re-occur year after year, they are to my garden... perennials. I was impressed a few years ago when visiting Mr & Mrs Nickolai near Loxton SA to see that they have culled their Ranunculus over the years and now grow a pure pink strain, to provide conbsitancy to the pink section of their garden.
Now admittedly some will be regarded as weeds somewhere in Australia. But let's face it, what plant is not a weed somewhere in this vast land. I struggle to grow Holly in Adelaide. Holly of any sort. Even Ilex paraguariensis.... yet most hollies are feral in Victoria, as I was reminded after I did a segment on television about them last winter. Incidentally on Ilex paraguariensis, which is the source of a bitter tea-like beverage that's very popular in Argentina, I have gown it from seed and my Mum has my plants growing well at Victor Harbor, but not on Adelaide's Alkaline clay. Please don't remind me of the weeds of Australia, that's your problem, not mine. I dispose of my prunings responsibly and I'd recommend you do too. If any of my favourite plants offend you, them come and live in a Mediterranean climate such as Neville Passmore and I do and you'll soon change your tune. We even love Lantanas! There I've said it! They thrive here and the selected cultivars do not set viable seed and do not spread into our bushland. I reckon Lantana 'Chelsea Gem' is stunning and hardly ever out of flower.
Where every you live there are gardens of inspiration for perennial and cottage garden aficionados. Every chance I get while in Melbourne I try to get to Herronswood, where Clive Blazey and his team of fanatically dedicated gardeners live out my dream of growing all the perennials I can only hope to. I know we grow some that they dream of too, which is comforting. In the Adelaide Hills at Lenswood, Don Kumnick on Kumnick Road, has a perennial garden that is amongst our best. It was originally open to view under the Australian Open Garden Scheme, but you know they rotate them a bit too frequently now and it's not open this year. It is however open privately throughout most of summer and it's a real treat if you live in the cooler foothills areas and can grow his plants. One that is way off the other end of the scale is the Richardson Garden also open privately all summer and it's on the hot drying plains of the Southern Vales at McLaren Vale. The McLaren Vale Tourist Information Centre in the main street will willingly re-direct you. This is a plantsman's garden that I visit often for inspiration and to buy plants. I reckon Dennis and Yvonne Richardson grow their plants so tough, they just have to survive in my patch and mostly they do. It's only when I know I'm 'crossing the line' in hardiness, that they fail.
I draw on a wide palette of perennials, native and exotic and I'm told some are annuals, but they keep growing for at least two years. I've had thickets of Tithonia rotundifolia "Mexican Sunflower" stay in flower all year. Admittedly many die down, but as soon as they do, others have strung up and the succession of flower remains unbroken. I have a few thickets of Daylillies, Tuberoses and Liliums too that die down too then bounce back. Some of my tender Liliums bounced back too soon this year and got cut down by frost in winter, because they were lulled into that false sense of security, by what started out as a mild winter in June and turned bitterly cold in July-August. They did however set enormous bulbils at the base of their stems that grew away rapidly in spring. It remains to be seen if they flower as well as last year.
Some of my most spectacular favourites are bulbs that can make a bold statement then virtually disappear again amongst the foliage of the more herbaceous perennials. In this category I love the "Kangaroo Paw' cultivars, such as "Little Joey" and his PBR mates. The Anigozanthos flavidus cultivars are very hardy on alkaline soils in Adelaide, where as the Anigozanthos manglesii and A. humilis cultivars prefer neutral well drained mounds to thrive. They get a Guernsey on my mulch mound, where the honeyeating birds tease the neighbourhood cats darting in and out of them all day. I love the Crocosmia cultivars too. The species (C. crocosmæflora and C. X pottsii, if they are the valid names) really are weeds in our bushland, but the "Bressingham" cultivars such as ' Lucifer' doesn't have enough vigour to be a weed. It's stunning flame like flowers in January-February can literally light up the garden as the flowers catch the first or last of the sun's rays.
The "Red-hot Pokers" or Kniphofia cultivars have a similar effect too and it's amazing how the pale yellow cultivars can flower in a shaded nook in the garden and bring it to light.
At the tiny end of the plant scale, I love Armeria maritima or "Thrift", that looks like Chives in flower. It needs full sun and excellent drainage and when grown close to Carnations, Dianthus and "Fairy Statice", it really looks at home. Also small and not to be overlooked if you have a slightly wild garden (read that as 'neglected' if you are not too sensitive), is the Wahlenbergia stricta, a native, that will happily self seed if left alone. For shaded areas that are pretty damp you can sink an old wash tub into the ground and plug the drainage hole with wood to create a bog garden. I find that's what needed to get Astilbe X arendsii forms to thrive in a Mediterranean climate. I'm sure you'll laugh at that if you live in the Dandenongs where I've seen them grow almost as weeds.
I'd call most bulbs corms and tubers.. perennials, so we can't overlook a few choice specimens here either. Alstroemeria cultivars thrive if a raised mound of humus rich mulch is provided for at least 30cm. Divide and replant in February though, when they will still make some growths before they die down for winter. Move them in winter when they are dormant and they take ages to recover, but they will. Many of the Lilium cultivars tolerate our predominantly alkaline soil, but given that it only needs a planting hole of 30cm deep to accommodate their acidic requirements, they are pretty easily catered for. Even L. longifolium can thrive given good drainage and acidic humus. Most of the modern Asiatic Lilium cultivars are dead easy and although the modern Hippeastrum cultivars are pretty expensive at first sight, they will last many years and are also easily maintained as potted plants rather than in the ground. While many of the South African corms and bulbs grow easily in the garden a more easily managed garden can be achieved by planting them in containers and if needs be, sink them in the ground so they appear to be growing. I've done that with Freesias, Dietes iridiodes, Ixia paniculata and Watsonia beatricis to thwart the spread of their corms. A little native that is often overlooked but thrives when left alone is Thysanotus. I'm not sure of the species since there are over 50 species that occur in all states and look similar, but it's a "Chocolate Lily" with that characteristic chocolate smell in the lilac flowers on long stems. Other bulbs that thrive in my locality are Scilla peruviana, that does not come from Peru, but Israel, Crinum asiaticum and Amaryllis belladona, called "Easter Lily" in SA, but it's generally well and truly finished flowering by Easter! The little Cyclamen miniatures that are mostly cultivars and selected forms of C. hederifolium, don't naturalise very well here, but in containers they thrive. Tulip cultivars and in particular those that do not need the crisper treatment in the fridge, such as the double 'Angelique' will grow well but really need digging up after they die down around Christmas time. Daffodils and Jonquils on the other hand naturalise easily, if they get plenty of sun and they are not given too much summer water. If you aim to establish Daffodils in the shade, which they will quite happily, you will need to replace their bulbs each year with fresh catalogue stock, because the bulb merchants supply you with a bulb that will flower in its first season, no matter what! After that it's a matter of how much sun and care they get as to whether they flower. The "Calla Lilies" that are Zantedeschia cultivars, should not be overlooked either for a late summer to autumn display in a Mediterranean climate. They are field grown under light shadecloth at Virginia on the Northern Adelaide Plains, which might surprise some local gardeners.
Some of the indestructible perennials need a mention too. The Achillea ordorata and some of the A. millifolium and A. filipendulina cultivars are hardy and send up flower spikes in white, pink and yellow respectively, that are quite stunning. They have a fairly invasive root-run, but nothing to loose sleep over! Sedum spectabile 'Brilliant' is a succulent for gardeners who have an aversion to succulents. The bed at "Herronswood", Dromana Vic. is as good as any I've seen in Europe, where they are held in considerably more esteem than in Australia. Low esteem is a reason why more "Dusty Miner" Centaurea cineraria is not grown more widely too, along with "Wallflowers" and "Stocks". Beats me why these hardy little harbingers of spring are so scorned. There are some fabulous autumn colours in "Wallflowers" Erysimum cheiri, leading from russet red-brown through to bright gold and yellow. The pink "Wallflowers" like the lilac flowering 'Winter Joy' are mostly hybrids with Erysimum linifolium.
While no one would attempt to name the cottage garden cultivars of "Marguerite Daisies" they are undeniably popular because they flower so easily and strike so easily from stolen cuttings! Another Daisy that gets overlooked by most gardeners except on Mothers' Day, is the Chrysanthemum, or whatever it is that taxonomists are trying to call it these days. Propagated from a runner or stool in July after they have discharged their flowering duties, they are suitable hardy enough for my garden. I grow the stools on until mid spring in pots then keep them cut down hard until January when I let them go to form flowering wood for a May show.
I grew some so-called Vinca 'Red Robin' from Erica Vale seed last year and they made stocky little plants with a sporadic flower last summer, but the frost cut them back in winter. They have recovered well and I'm expecting big things from them this summer. They are the "Madagascar Periwinkle" also known as Cartharanthus and not to be confused with that rambunctious ground cover, Vinca major or the similarly named "Snail Creeper" Vigna caracalla.
Now on to climbers. They tend to get left out of texts on perennials. The "Coral Vine" Antigonon leptopus is stunning in April on a fence. It dies back to a rootstock in winter as does the "Snail Creeper" already mentioned and Cobea scandens the "Cup and Saucer Vine". Another hardy vine I almost fear mentioning is the "Morning Glory" but it makes a respectable specimen in a large container and is the ideal seaside vine, where it surely get neglected by itinerant guests. The Convolvulus cneorum is a charming and well disciplined silver leafed shrub to half a metre that also grows well at the coast or in a cottage garden.
There are so many favoured perennials I have yet to mention, please indulge me just a little longer. How can I not mention the Correa reflexa forms to you, or Coreopsis "Early Sunrise", the "Double Hollyhock", that grows as a perennial in my garden, regardless of what your texts say. A think all shaded gardens on clay soils must find a spot for the foliage plant Acanthus mollis and maybe its thin-leaf relative, Acathus caroli-alexandri. The flowers are a bonus, but the foliage never looks out of place. If you can grow these then Hellaborus guttatus should also be known to you. Its green flowers in mid winter, make up for its anonymity for the rest of the year.
Some woody plants such as some of the small Acacia species, deserve a place too. They look best when replaced every three years anyhow. Acacia acenacea, A. spectabilis and A pulchella are all worth a second look. The Hebe buxifolia and so many of the "Whipstick Hebes" from New Zealand also respond well to a total number 2 clip every three years, so that they make fresh growth and flower again with vigour. Jacobinia pauciflora and Penstemon 'Van Hahn' also need the same treatment. Some of our native Calytrix like C. alpestris and tetragona, also make better flowers when cut back really hard every two to three years. The ground cover Lotus bertholetii in red or golden forms needs to be replaced every two years or they seem to kill themselves, for some reason. Fortunately they strike easily from cuttings so make sure you always have some coming on.
A few combinations that just have to grown together are Salvia leucantha, with its grey woolly foliage and fine lilac spike of flower alongside Phlomis purpurea and make sure there is room nearby for a fairly recent cultivar, Salvia coccinea 'Coral Nymph'. Plant Hypoestes aristata and Iresine herbstii together and they look stunning in April. The native Thomasia grandiflora var. angustifolia planted near Boronia denticulata also makes a lovely combination, with Scaevola aemula 'Purple Fanfare' at their feet, as a ground cover from August to October. In really hot spots Hemiandra incana with its grey foliage and pink flowers from January to March looks a perfect compliment to a drift of Lisianthus and Nierembergia hippomanica var. violacea or Felicia fruticosa if you are near the coast.
With so many perennials in our cottage garden now, there is hardly any room left for annuals, but winter flowering annuals like "Matilda Poppies" and all your favourite Pansies, will always take some beating. As for the perennial problem of weeds in the garden, I thank my lucky stars that glyphosate is still a pretty safe product to use and it works miracles when used as a daub to control unwanted seedlings. Even with good weed control, perennials still mean work and lots of it.