FLORAL FRAGRANCE IN THE GARDEN

The most fragrant flowers are generally smaller and less colorful than less fragrant flowers. This angel’s trumpet is an exception.

Attracting pollinators is serious business for flowers that do not rely exclusively on wind for dispersion of their pollen. Many flowers attract pollinators with flashy color. Some reward their pollinators with sweet nectar. Many prefer to use fragrance. Most flowers use a combination of two or more of these tactics.

Fragrances are designed by the flowers that use them to appeal to the discriminating taste of specific pollinators. Most are sweet. Some are more perfumed. A few are even quite objectionable to people because they are tailored to flies. Fortunately, flowers with foul fragrances are rare in gardening.

The most fragrant flowers are often less abundant than flowers that rely on wind for dispersion of their pollen, or less colorful than flowers that rely on visual appeal to attract pollinators. Yet, the fragrant flowers of wisteria vines and lilacs are both profuse and colorful. The surprisingly big and fragrant flowers of ‘Charles Grimaldi’ angel’s trumpet are bright yellow.

Mock orange (Philadelphus spp.) conforms to the stereotype of fragrant flowers a little bit better, with somewhat small white flowers that are incredibly fragrant. The small pale pink flowers of daphne are even less impressive and nearly hidden among their foliage, even though their fragrance can not be ignored. The sweetly fragrant flowers of Japanese honeysuckle vines are abundant but not too colorful. Star jasmine vines likewise bloom fragrantly and abundantly, and their bright white flowers contrast better against their glossy green foliage.

Night blooming jasmine is not appealing enough for prominent placement, and is not even fragrant during the day, but will be unbelievably fragrant on warm summer nights. Just as fragrances appeal to specific pollinators, nocturnally fragrant flowers specifically appeal to insects or bats who are active at night.

Freesia, hyacinth, lily,narcissus and some types of iris are very fragrant as well as colorful now that they are blooming for early spring. It is unfortunate that their flowers do not last long, and that there are not any comparable flowers later in the year. The same annual sweet peas and stock that bloom about now can be planted again later for autumn bloom. Sweet peas are easiest to grow from seed. Stock is easiest to grow from cell packs, and since it is actually perennial, sheltered plants can survives through warm summer weather to bloom again in autumn. Annual sweet alyssum can bloom anytime while the weather is warm.

Fragrant Flowers Often Lack Color

Unremarkable flowers can be remarkably fragrant.

It is presumptuous to believe that all the fancy breeding that is done to enhance the characteristics of flowers necessarily ‘improves’ them. Breeding only makes flowers more appealing to those who enjoy them in their gardens. Most flowers were already quite efficient for their intended function in their respective natural habitats long before humans started tampering with them. As far as flowers are concerned, they only need to get pollinated.

Some flowers use flashy color or patterns to be visually attractive to pollinators. Others use fragrance to be olfactorily appealing. Small but profuse flowers that are neither colorful nor fragrant have given up on insect or animal pollinators, so instead rely on the wind to disperse their pollen.

Not many flowers are both remarkably colorful and remarkably fragrant like freesia, lilac and wisteria were earlier in spring. Lily and bearded iris are of course very colorful, but not all types are fragrant. The big and bold flowers of cereus cactus, moon flower and angel’s trumpet are only fragrant because they bloom at night, and rely on nocturnal  pollinators who benefit from a bit more guidance in the dark.

Many fragrant flowers are somewhat showy, like gardenia, star jasmine, pink jasmine and honeysuckle. (However, gardenia are almost never healthy and showy locally.) Many of the most reliably fragrant flowers are really not much to brag about. Pittosporum tobira, Pittosporum undulatum and sweet osmanthus are known more for the appealing evergreen foliage than for their small and nondescript flowers. The flowers of sweet osmanthus may actually be difficult to find amongst the obscuring foliage. Night blooming jasmine is sometimes planted around corners or in the background because even the foliage is not too appealing, although the powerful candy-like fragrance is a favorite for warm evenings.

Fragrant flowers can be annuals like sweet alyssum, bulbs like hyacinth, or perennials like tuberose. Woody plants with fragrant flowers can be vines like stephanotis, shrubs like mock orange (Philadelphus spp.), or trees like Southern magnolia. Some have brief bloom seasons, while others bloom for quite a while.

Fragrant Flowers Have Ulterior Motives

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Demure daphne bloom is richly fragrant.

Many who enjoy gardening appreciate fragrant flowers. Many grow particular flowers specifically for their fragrance. Yet, not many consider why so many flowers are fragrant. Plants can not enjoy their own alluring floral fragrances any more than they can enjoy their own delightful floral colors and forms. They do not expect people to enjoy their bloom either. Human appreciation is incidental.

Floral fragrance is merely intended to attract pollinators. Flowers are inanimate, so rely on either wind or animate pollinators to exchange their pollen among other flowers. Animate pollinators are mostly insects, but may be birds, bats or other animals. Flowers do what they must to attract their preferred pollinators. Many use color and floral form. Many use fragrance. Some use both tactics.

Flowers that use both color and fragrance to attract pollinators are mostly endemic to densely forested ecosystems. There is more competition for pollinators within such ecosystems than there is within ecosystems of sparser vegetation. Otherwise, fragrant flowers are generally not as colorful as those that are not as fragrant. Likewise, the most colorful flowers are generally not so fragrant.

Angel’s trumpet is striking in bloom because the flowers are so large. Wisteria and lilac that bloomed last spring were spectacular because they were so profuse. The pastel hues of their blooms are no problem that their fragrance does not compensate for. Pink jasmine and mock orange are about as fragrant, even if their color range is more limited. Star jasmine is not always so profuse.

Pittosporum tobira and Pittosporum undulatum are even less visually impressive in bloom, but can be surprisingly fragrant. The tiny but richly fragrant flowers of sweet osmanthus, sweet box and night blooming jasmine are so obscure that other bloom is often credited with their fragrance. As the name implies, night blooming jasmine is powerfully fragrant after sunset during warm weather.

Freesia, hyacinth, narcissus, lily and some bearded iris are both colorful and very fragrant.

Horridculture – Stinky Flowers

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Rhody was not impressed, and he is an expert on fragrance.

Dracunculus vulgaris – dragon lily. It was featured in the gardening column for next week, both as an illustration for the main topic, and as the ‘highlight’ species. It is as unappealing as the name and the pictures suggest, but it sure is interesting. It has several more equally unappealing common names. We know it as ‘death arum’ because that is the first name we came up with.

Besides, it smells like death. Yes, it stinks. It does so to attract flies for pollination. Actually, it attracts quite a few annoying insects. I can not explain why, but insects who congregate around stinky flowers are as unappealing as the fragrance that draws them. They are certainly very different from the appealing bees and butterflies who pollinate flowers with appealing fragrance.

The first of these death arums mysteriously appeared in the garden of a colleague several years ago, and promptly multiplied by both seed and disbursement of tubers. There are now a few expansive colonies that continue to expand. Cutting down the foliage does not slow them down much. The fragrance, which is not too bad individually, is getting to be bothersome collectively.

My colleague brought me one of the tubers to confirm the identity. I got a picture of it since it was here, but then did not know what to do with it. I did not want to toss it aside into the forest like I do with so much other greenwaste. It could have grown into a problem. I did not want to discard it either, since it was viable and healthy. So, I canned it and put it aside in the nursery.

This is the result. It is not as stinky as I expected it to be. I still do not know what to do with it.

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These unidentified beetles that I had never noticed here before arrived promptly for the stinky bloom.

 

 

 

Sweet Box

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Foliage of sweet box outdoes flowers.

While bloom cycles of most plants are accelerated by the unusually warm winter, sweet box, Sarcococca ruscifolia, seems to be blooming a bit late. It should have bloomed sometime in winter, and finished a month ago. The tiny pale greenish white flowers are certainly nothing to look at, but they produce a remarkably rich fragrance that seems like it would be delicious with coffee.

The foliage is very glossy and dark green, like that of English holly, but the leaves are small and lack spines. Red berries sometimes develop, but are only abundant enough to be notably colorful on plants that are distressed. Sweet box may take a few years to get established and grow to only about three feet high and wide, although it can slowly get a bit larger.

Since it is naturally an understory plant, sweet box prefers at least a bit of shade. Harsh exposure fades foliage. Because of its tolerance of partial shade, as well as its low and dense growth, sweet box is ideal for obscuring foundations. After the first few years, it does not need too much water. It gets established more efficiently in rich soil.

Good Looks Are Not Everything

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Less color can mean more fragrance.

More flowers bloom as winter becomes early spring than at any other time of year. For many flowers, bloom is significantly accelerated this year because winter was so very warm. Flowering cherry, purple leaf plum and most of the stone fruit trees (such as almond, cherry, apricot, nectarine, peach, plum, prune and all their various hybrids) have already bloomed.

Color is what gets noticed first. After all, that is what all the flashy colors are intended for, to get the attention of pollinators. Yet, there is more to the indirect mating strategies of flowers than color. Because flowers lack the mobility to pollinate each other, they do what they must to attract others to disperse their pollen for them. Some use fragrance.

Generally, flowers prefer one tactic or the other. This is why the most colorful flowers lack fragrance, and the most fragrant lack color. Gardenia (which is not easy to grow locally), star jasmine, honeysuckle, Pittosporum tobira, Pittosporum undulatum and night blooming jasmine are not exactly colorful while blooming. The powerfully fragrant flowers of sweet osmanthus and sweet box barely get noticed.

Pink jasmine and mock orange (Philadelphus spp.) are flashier, only because their blooms are so profuse. Southern magnolia has spectacularly big flowers, but they are mostly obscured by dense foliage high above view. Cereus cactus and moon flower are likewise spectacular, but bloom at night to attract nocturnal moths for pollination.

Only a few flowers are both colorful and fragrant. Lilac and wisteria are among the more familiar. Both bloom early in spring, with a similar color range of lavender, blue, pink and white. Lilac is shrubby. Wisteria is an aggressive vine. ‘Charles Grimaldi’ angel’s trumpet is a big shrubby perennial that blooms rich yellow, but may only be fragrant at sundown.

Freesia, hyacinth, lily and bearded iris are flashy and fragrant flowers grown from bulbs, although hyacinth and most lilies rarely bloom a second year, and many lilies and bearded iris lack fragrance. Sweet alyssum is a mildly fragrant annual that blooms white, pink or lavender.

Scented Geranium

60511Window boxes were supposedly invented in Venice to contain aromatic plants that repelled mosquitoes (and probably because garden space was so minimal in Venice). Hanging plants like nasturtium and ivy geranium are traditional window box plants because they do not obscure scenery or sunlight. Scented geraniums are also popular because they are be so strongly aromatic.

Scented geraniums are of the Pelargoniuim genus, so are related to ivy and common geraniums, but are a mix of a few different specie and hybrids. Their foliage can smell like rose, lemon, orange, apple, strawberry, ginger, mint or other herbs or spices. Specialty geranium growers may have nearly a hundred varieties to choose from, which is less than half of the known varieties.

Not many scented geraniums bloom with impressively colorful flowers. However, many have interestingly textured, colorful and lobed foliage that might be velvety or even raspy. The more compact varieties stay less than a foot tall, and spread laterally very slowly. Others have longer but limber stems that lay low as they spread like sloppy ground cover. A few stand upright as tall as five feet.

Herbs Add Spice To Life

80207thumbOut in deserts, where vegetation can be a scarce commodity, cacti, agaves and yuccas protect themselves from grazing animals with thorns, spines, caustic sap and distastefully textured foliage. None of these defense mechanisms is perfect. They only need to be better than what the competing specie are using. Many plants find that objectionable flavor and aroma work just fine for them.

The funny thing about the objectionable flavors and aromas that some plants use to discourage grazing animals from eating them, is that these same flavors and aromas are what make so many of them appealing to people. It is ironic that what was supposed to make them distasteful to some is what makes them tasty to others. Yet, it also gets us to perpetuate them in our home gardens.

Mint, thyme, lavender, rosemary and sage, which all happen to be in the same family, are culinary herbs that also work well in the landscape. The mints need the most watering, and containment if their innate invasiveness is a concern. Thymes need less water, and some are nicely aromatic ground cover for small areas. Lavenders and rosemaries can survive with minimal watering here.

Both rosemary and sage are popular for landscaping anyway. Rosemary is most commonly grown as a ground cover that cascades nicely over low retaining walls, but some cultivars are shrubby. Sages are extremely variable. Some are showier than they are useful in the kitchen, with elegant and colorful flower spikes. Others are too strongly aromatic to cook with, but are used as incense.

Fennel and chamomile are often grown in vegetable gardens rather than out in the more refined parts of the landscape because they can get somewhat awkward. Fennel has such nice feathery foliage at first, but if not harvested, it gets tall, and then yellows after bloom. Chamomile gets tall and open in bloom, and then no one wants to ruin it by harvesting all the flowers if it looks too good. Chives are easier to work with. They have so many leaves that no one misses a few taken for the kitchen.