Fragrance in the Garden

This dwarf butterfly bush called Buzz Hot Raspberry attracts butterflies and smells delicious.

Last year I bought a dwarf butterfly bush and planted it in a pot near my entry. I?m not sure if it?s a Buzz Hot Raspberry or a Lo & Behold Pink Microchip but it?s in full bloom and will continue through fall if I keep it deadheaded. The swallowtail butterflies love it and the scent is so sweet and so strong I can smell it through an open window. In this time of hanging out more at the homestead it brings a smile to my face.

Fragrance in flowers is nature’s ways of encouraging pollination. Just as it draws you to take a deeper whiff, it lures insects to blossoms hidden by leaves. Some flowers are fragrant only at night and attract night-flying pollinators like moths, while others are more fragrant during the day and attract insects like bees and butterflies. The fragrance itself comes from essential oils called attars that vaporize easily and infuse the air with their scents.

Aroma chemistry is complex and the smell of any flower comes from more than a single chemical compound. These molecules are present in different combinations in different plants, but often they are markedly similar which is why there are irises that smell like grapes and roses that smell like licorice. Our noses can detect those chemical compounds that have a major impact on the aroma. Often a particular molecule will make a large contribution.

Some roses, for instance, derive their scent from rose oxide and others from beta-damascenome or rose ketones. These molecules are detectable by our noses at very, very low concentrations. Carnations, violets, lilies, chrysanthemums, hyacinth- all have their own set of compounds that contribute to their scent.

It?s interesting also that as we become accustomed to the same smell our brain phases it out. A compound called ionones, found in violets and rose oil, can essentially short-circuit our sense of smell, binding to the receptors. This shut down is only temporary and the ionones can soon be detected again and registered as a new smell.

Place sweet-smelling plants where you can enjoy them throughout the season. The potency of flower scents varies greatly, so consider the strength of a fragrance when deciding where to put a plant. Subtle fragrances such as sweet pea. lemon verbena, scented geranium and chocolate cosmos smell wonderful right outside the back door. Add stronger scents by your deck, pool, spa, dining area or gazebo. Stargazer lilies, jasmine, lilacs, daphne, citrus and peonies will make you want to stay awhile.

Several easy-to-grow shrubs have fragrant flowers as an added bonus. Mexican Orange (choisya ternata) blooms most of the year. Pittosporum eugenoides, tenuifolium and tobira all have tiny blossoms that smell like oranges. too. The tiny flower cluster of Fragrant Olive (osmanthus fragrans) have a delicate apricot fragrance.

Other fragrant plants include California native Philadelphus lewisii (Wild Mock Orange). Calycanthus occidentals (Spice Bush) is native to our Central and Northern California mountains. Their fragrant burgundy flowers smell like red wine. Ribes viburnifolium, carpenteria californica and rosa californica are mildly scented, too.

In spring there may be nothing quite as spectacular as a wisteria vine, loaded with fragrant purple, pink, blue or white flower clusters, covering an arbor or pergola. Pink jasmine is another vigorous vine with intensely fragrant flowers as is Evergreen Clematis.

I can’t leave out the old fashion border carnation or dianthus. Their clove-scented flowers are born in profusion making them a nice addition to the mixed flower border and containers.

The list goes on and includes scented plants such as nemesia, wallflower, Japanese snowbell, hosta, coneflower, vitex, viburnum, nicotiana, phlox, rose, sweet pea, hyacinth, lilac, flowering crabapple, heliotrope, lavender, sweet alyssum, peony, moon flower, southern magnolia.

Angel?s Trumpet grow well in containers. Their dramatic, fragrant flowers scent the evening air.

Be sure to include fragrant plants that release their scent in the evening, especially in the areas of the garden you most frequent after dark. Since the majority of night-scented blossoms have white flowers, these plants also light up the landscape at night. Angel?s Trumpet (brugmansia) is one such plant as is flowering tobacco and night blooming jessamine.

Plant vines for fragrance in your garden. Evergreen clematis (clematis armandii) bloom with showy white fragrant flowers clusters above dark green leaves in the spring. Clematis montana is another variety of clematis that?s covered with vanilla-scented pink flowers in spring also. Carolina jessamine’s fragrant yellow flower clusters appear in masses from late winter into spring.

Ideally, when you’ve finished, your garden will smell as intriguing as an expensive perfume. The top note will be floral- jasmine, honeysuckle, rose. The middle register will be spicy, such as the vanilla of heliotrope or purple petunias or the clove of dianthus. Finally underneath, the tones that give perfumes their vigor, like artemisia, sage and santolina.

Not every inch of the garden needs to be fragrant but a waft or two of fragrance from the right plants can turn a garden from ordinary to enchanting.

Watering 101

This combination of Safari Sunset leacadendron, Guardsman phormium and succulents has low water needs.

Is your garden starting to look a little bedraggled? After a few hot spells, have the plants in your yard gotten a taste of what?s to come for the rest of the summer? After you?ve chosen climate adapted plants how much water do they really need? Here?s how can you keep everything happy and not waste water.

All plants need water- even those that are tolerant of our summer dry conditions. Water makes up 90-98% of every plant we grow. It’s needed for photosynthesis, as well as reproduction and defense against pests.

With summer water bills arriving this is a good time to re-visit how often and how much to water that landscape you?ve spent so much money to create. Basically, you?re wasting water if you?re not watering deep enough to moisten the entire root ball or if you?re irrigating too often.

Photosynthesis is one of the most remarkable biochemical processes on earth and allows plants to use sunlight to make food from water and carbon dioxide. At temperatures about 104 degrees, however, the enzymes that carry out photosynthesis lose their shape and functionality. A garden that provides optimum light and water but gets too hot will be less vigorous.

Plants have natural systems that respond to heat problems. Plants can cool themselves by pumping water out through the leaves for a kind of swamp cooler effect. They can also make ?heat-shock? proteins which reduces problems from over heating. All these strategies can take resources away from a plant?s other needs like growth, flowering and fruiting.

So how much water do different types of plants need during the heat of summer?

Be sure that you water trees and shrubs deeply, checking soil moisture first with a trowel. Established small to medium shrubs should be watered when the top 3-6 inches of soil is dry. Water large shrubs and trees when the top 6-12 inches is dry.

As a rule of thumb, trees and large shrubs need deep but infrequent irrigation. They should be on a separate valve than your smaller shrubs and perennials. Water ornamental trees 1-3 times per month depending on the type and soil. Tree roots grow 24-36 inches deep or more and require 10 gallons of water per inch of trunk diameter.

California native mimulus auritanicus

Apply water with a soaker hose, drip system emitters or hand held hose with shut off and soft spray attachment according to your water district?s restrictions. Don?t dig holes in the ground in an effort to water deeply. This dries out roots even more. Be sure to water the root zone to the indicated root depth every time you water. Watering deeper than the root zone only means you are wasting water. You can test how deep you watered by pushing a thin, smooth rod into the ground soon after you irrigate. The soil probe should easily slide through the wet soil but become difficult to push when reaching dry soil.

The roots of smaller shrubs reach 12-24 inches deep in the soil. Established native shrubs may need only monthly watering to keep them looking their best while other shrubs may need watering every 7-10 days during the heat of the summer. Perennial roots only go down 12 inches or so and may need watering once or twice a week depending on type.

When is the best time to water? Watering in the morning is the most efficient whether you water by sprinkler, drip system, soaker hose or by hand because the water soaks deep in the soil without risk of evaporation. This bolsters the plant for the day and has dried from leaves by evening reducing the risk for foliar diseases like mildew. Plant roots are also more receptive to watering in the morning.

Is it true that water droplets will scorch leaves in the midday sun? According to a study, fuzzy-leaved plants hold water droplets above the leaf surface and act as a magnifying glass to the light beaming through them so there is a very slight chance of scorch.The study also reported that water droplets on smooth leaves, such as maples, cannot cause leaf burn, regardless of the time of day. But no matter the time of day, a plant that needs water should get the right amount.