Fragrant Plants: The Nocturnal collection  by Malcolm W. Campbell

Some of the most fragrant nocturnal flowering plants are the vines and creepers such as Jasminum polyanthum, "Sweet Peas", Wisteria floribunda, Mandevilla laxa and Lonicera species and cultivars. I particularly like Lonicera hildebrandiana especially if you can keep the humidity up to it.

The following recommendations, are offered according to my recollection of their perfumes at night.

These are fascinating night plants and their modern breeding has made much of their perfume. The resurgence of the old-fashioned highly fragrant strains of veined lilac blooms on cultivars such as 'Sugar Plum', which has long since disappeared from the bedding flower trade lists, has made a welcome comeback in the cultivars such as the 'Madness Plum Crazy', 'Stereo' and 'Waterfall' series. The characteristic contrasting lilac morn or throat is now a feature of these lines. Even some of the much paler modern cultivars, such as 'Flamingo' which has a pale pink flower and contrasting cream morn, is also very fragrant at night. Being a paler colour it also makes a better contrast under lights at night than the predominantly blue and lilac forms already mentioned.

There are five main groups of Petunias that have emerged in recent breeding and fortunately all of them have fragrant blooms over most of the warm part of their growing season. In the tropical and sub tropical areas they are grown as dry season bedding plants and in the cooler southern states they make reliable display beds after the frosts have gone, right through the warmer weather, in all but our coldest mountain gardens. Most petunias also make excellent container groan plants and when in flower they can be brought indoors for a night of entertainment to thrill you and your guests with their evocative perfume. Most adults can recall being pushed into a bed of Petunias a as child and smelling of the tell-tale odour for hours. I certainly can, much to the chagrin of my gardening father on more than one occasion. Worth mentioning that most of the

The five categories of Petunia are seed suppliers' classifications rather than strictly botanical, but they certainly do help to differentiate the plethora of cultivars available these days.

The 'Grandiflora' types are the largest plants and flowers. The taller habit makes them ideal for the back of a wider border or to be used to create height to a flat bed. Their 6-8cm flowers are generally fluted or ruffled and the most popular cultivars are 'Colour Parade', the 'Flash' series and 'Royal Velvet', with 'Bonanza' and Heavenly Lavender' being double 'Grandiflora' types. One draw-back from growing 'Grandiflora' petunias is that they resent overhead watering, since they collapse pretty easily, but they do make lovely pot plants where they are watered by hand or from drippers, so that their canopy is not weighted down.

The 'Floribunda' types have flowers of 5-6cm in diameter on smaller bushes, but with considerably more blooms per bush. Because of the more compact plants, they are better able to withstand the wind and can be watered overhead. The 'Waterfall' and 'Stereo' series are two of the most popular 'Floribunda' Petunias. Both have named cultivars for the individual colours that make up the series and they are popular with corporations and keen home gardeners who seek to create colour co-ordinated bedding schemes. 'Polo Burgundy Star' is a lovely 'Floribunda' cultivar, but it's generally used in bold blends rather than as a stand alone offering.

The 'Multiflora' Petunias have 4cm flowers on compact procumbent bushes. That makes them popular with coastal gardeners, where the bushes don't get blown apart and they also seem to be the hardiest of all Petunias. So for the neglectful gardener or the novice none-to-sure of their horticultural skills, a few punnets makes a wonderful gift. They need to be planted at 30cm centres, so don't be too stingy when you buy them! 'Super Dazzler' and 'Flair' make up two of the brightest 'Multiflora' series.

The latest Petunia type is the little 'Milliflora' with masses of 2.5cm blooms on extremely compact and prostrate bushes. This makes deadheading them very easy. You simply set the lawn mover at about 7cm after Christmas and with a flourish over the beds, they will return to fresh blooms within four weeks. Of course with a brush trimmer you can do that to any of the Petunia types, but the dramatics over such small plants really gets the neighbours' tongues wagging. The 'Lullaby' series is the pet of this type and it's also available in a separate cherry red and white.

The fifth type of Petunia is the Sunlover™ "Perennial Petunia", known as 'Purple Craze' to most gardeners. The other types of Petunias are of course all treated as annuals, so a perennial stands apart in the garden because it needs a very different setting. First released in 1993 as a purple only flower, there are now other colours available. They are best cut back to a stump each year in the cold non-growth season. They will spread to a sprawling ground cover over 3 or 4 square metres in a summer. That has made them popular with unit owners who container garden and with folk who have some very steep slopes to cover. As with all Petunias they need a sunny well drained spot in the garden to flower at their best. In warm Mediterranean gardens it is advisable to cut them back after their first flush of flowers, but since most gardeners want a Christmas display, that usually gets delayed until early January.

The "Spider Flower" or Cleome hassleriana (syn. C. spinosa) is an annual that loves a hot humid site and it will make at least 1.5 metres in height, if grown well. It's perfume rises as the sun sets and because of its concealed spines on the stems, it makes an excellent barrier plant to stop uninvited guests. Plant it along a fence line with smaller and friendlier Petunias at their feet and the fragrance is stunning. Australians are not particularly adept at describing the 'notes' of fragrance from flowers in our gardens, but what ever it's called it's heavenly on a warm evening. I think the appeal of Cleome is that it takes the acrid smell of a barbecue away. When I was a TAFE horticultural lecturer, a student one told me that it was the world's best cover crop for "Mary Jane". They have huge complex flowers the size a clenched fist in pink, burgundy, lilac and white, but I think it looks best as a mixed bed, because the white bushes are a little lacking in the vigour of the lilac and burgundy flowering bushes.

Cosmos atrosanguineus is the "Chocolate Cosmos" and absolutely essential for the Choco-holic's night garden. It has brown flowers so it won't stand out in the night garden but its perfume certainly will. Plant seedlings with the white flowering form, that are sold separately in nurseries and the effect will be quite striking. The white blooms are also fragrant, but it's the chocolate ones that will heve the guests talking. Cosmos are most forgiving annuals. The sort of flower you could plant down the coast at the weekender and still expect them to be alive if you missed a few weekends.

Another chocolate fragrance that is a native of southern woodlands is the native Thysanotus multiflorus or "Chocolate Lily". I've noticed that there is quite a supply of it on the market this year, for the first time, so don't rule that out either, at least for a container specimen. It's a perennial with glaucus grey strap-like leaves and makes a lovely clump over a few years flowering with many pink blooms to each spike, over quite a period in spring.

These are plants with an identity crisis variously known as Datura, Methysticodendron, "Angel's Trumpet" or to 70's flower-power geriatrics as "Donavan's Mellow Yellow". They are escape weeds in the warm humid regions of the east coast woodlands, yet very hardy small trees in Mediterranean Adelaide and Perth. The large white fragrant flowers against the enormous leaves, make this a most attractive plant, when it's pruned to tree shape. Otherwise it wants to become a scrambly open shrub. The new apricot cultivars are just as fragrant and prolific as the white forms. Don't try smoking the flowers, the hallucinogen can render you blind, at least for a few days!

These are tropical trees a fact often forgotten by gardeners, when locating them in the southern garden. They need a north facing wall with summer water to flower best and resist the temptation to fertilise them with too much nitrogen. This is by far the most common reason as to why they fail to flower. There are some lovely colours in the tropics, but the most reliable in southern gardens are the palest colours. They make good container specimens and a half hogs-head (wine barrel) will keep one flowering for at least 20 years.

To most gardeners these are still known as Cheiranthus or "Wallflowers". The Erysimum cheiri "Moonlight' is a new cream flowering "Wallflower" that makes a good evening contrast under lights in the evening garden as well as having a delicious exotic perfume at night and flowering in early spring through to summer is an added bonus. All of the "Wallflowers are fragrant, however most have dark coloured flowers that don't provide much contrast in low light.

Mandevilla laxa the "Chilean Jasmine" is a most fragrant white flowering creeper at night. It has luscious looking leaves and masses of tubular white flowers with a very welcoming perfume at night. The vine can be easily contained using electric hedge trimmers twice a year. If you want a pale pink flowering form to match the terra cotta features at poolside, then Mandevilla sanderi 'Pale FaceŽ' would interest you. Its fragrance is no where near as strong as M. laxa, but the flowers are much larger. I've had one growing in a pot for the past two years and it hasn't spotted flowering. I recently planted it into its final resting spot in my Wayville SA garden, where it is not that keen on the clay soil, but with some mulch and a treatment of iron chelates it's coming around. So if you garden on very alkaline clay, you might grow it in a pot. It certainly thrives in quite small containers.

The annual flowering stocks both single and double forms make excellent winter and spring flowering fragrant plants, but you need to have the seedlings planted by April to get the best display. Too many gardeners think winter for planting stock. They will grow and flower, but their bushes will not have matured enough to bear really large spikes of flower. In Egypt they are revered as a winter bridal flower and hand wired by the thousands to form garlands and floral arches. For alkaline clay soils they are one of our very best annuals, having gone wild along some of the south coast beaches near Port Elliot and Victor Harbor SA. (Yes we spell Harbor that way in SA)

The poor old Pelargonium gets left out of everyone's want list, when it comes to fragrant plants, but I reckon it's one of the best. Especially if you garden on alkaline soils, as I do or if you have to endure Adelaide's reticulated River Murray water to irrigate it. The "Ivy-leafed Pelargoniums" make easily maintained climbers for a sunny spot and can be used quite skilfully in tiny areas, against fences or in the street where they may be prone to the odd spate of vandalism. There are dozens of named cultivars and they mostly have a lovely perfume that comes from the foliage as much as the flowers, so locate them where they may get brushed as you pass by. The smiling white flowers of Pelargonium peltatum 'Scatatum' is a favourite where ever Pelargoniums are grown. 'Beauty of Jersey' is a rich red flowering one, but since most folk get their Pelargoniums as a cutting from a friend or from the local trading table in the high street, named cultivars are often lost, but given the superb forms available these days it really is worth searching our some of the better cultivars.

The fragrant flowers of Gardenia augusta 'Florida' are a legend. One of the most common complaints that I get on radio is "My Gardenias won't flower and the leaves are going yellow with green veins". Gardenias, love acidic soil that's nitrogen rich, so that's the solution. I had a garden in Kathmandu with a Mali or gardener who used to relieve himself every night on the Gardenia hedge just before knocking off. That hedge was the best I've every seen. He chose a different spot every night, always remembering where he went on the last occasion and over Dasain (a fifteen day holiday in Nepal), I kept up with the feeding! So now you know what to do, but I do recommend that you water it well or if applying from a bucket (out of modesty or deference to the neighbours) that you add five times the volume in water to break it down or it may prove a bit rich and burn the leaves.

There is also a Gardenia thunbergii in the Adelaide Botanic Gardens that is a lovely 8 metre spreading tree, but it looks quite old, so it may not be the choice if you are a gardener in a hurry. 
The new prostrate Gardenia cultivars are well worth growing too.

Peter Valder's book on Wisteria has made them popular one again, thank goodness. They are certainly one of our best fragrant spring flowering vines and grown all over the country. The art to flowering them well is to prune them religiously every year and to head them back as you would your pumpkins and for the same reasons. If the vine is still making lots of soft tip tendrils it won't flower very well. but once those are pruned then it matures quickly and forms old wood from which the flower spike will shoot. They can be pruned back to the same position each year and kept flowering for a century. I just hope that some of the wonderful cultivars featured in Peter Valder's "Wisterias" book find there way into Australian nurseries soon.

The rich smell of cloves is a great characteristic of those old-fashioned Pinks and Carnations and in the still of a warm spring night it wells to perfection, beckoning you to go explore the source in the garden. The Modern Dianthus cultivars don't seem to have the clove perfume that the cottage plants have, so look to Dianthus 'Allwoodii' cultivars that are in flower so you can select the best fragrances.

Buddleja davidii cultivars certainly attract the butterflies and moths at night so I guess they are perfumed. I see that Erica Vale sell the seed in their packet range and I have spotted some dwarf forms around, if you can't spare the 3x3 metre spread they require. They form large bottlebrush like spikes of flowers on the end of weeping canes. Buddleja alternifolia makes a big shrub to 7 metres and has small lilac flowers all summer. Buddleja globosa has 2cm golden ball like flowers that are very attractive and have a delicate perfume on a warm summer's night.

There are some lovely "Sweet Peas" that have delightful fragrance at night and grown from April-sown seed they flower quickly in spring. They are also a most welcome cut flower indoors too. You might find the perfume a little too over-powering in a small room though. The 'Gawler Strain' bred by the Martin and McDougall families in Gawler SA and frequently offered for sale in the national gardening magazines and to my nose are the most fragrant. The 'Gawler Strain' is characterised by long stems, with relatively few flowers on each spike, but masses of spikes over quite an extended season in spring.

The Oenothera species and cultivars are quite popular perennials in fragrant gardens and at night they are just as welcome as during the heat of the day. Beware to locate them where you can control. them, because they have a habit of self-seeding rather profusely, if the site suits them. The pale pink forms of O. speciosa are most popular, but don't overlook the yellow flowering Oenothera macrocarpa (syn. O. missouriensis) which is a much hardier plant in hot situations.