Dahlias

I can’t remember when I first experimented with growing dahlias but it was love at first sight. Now I find myself making space to grow more each year. Once you’ve had success with growing your own you may be hooked too. The color range is unbelievable and they’re super fun.

Here’s one with white-tipped petals bleeding into fuscia and deep cherry (unknown variety). A wide range of types are available - cactus, pompom, dinnerplate, waterlily, dwarf, specialty and more with flower sizes ranging anywhere from 2 inches to 10 inches or more. Dahlias originate from Central America and are grown as annuals in cold climates. They must be dug up and stored in cool dry locations and replanted once the ground has warmed. They’re slow to flower but the show is worth the wait.

Below: Ruby hued petals unfold after a rain shower in mid-September. The flowers appear late in the season, usually starting in August, and will keep producing until hard frost. When staked they can withstand heavy downpours without breaking.

Smaller single types don’t require support and are best sited near the front of a border, along a walkway, or used in pots. I first encountered the unique variety below in the Seasonal Walk at the New York Botanical Garden and later found it online - it’s called Bashful - one of my favorites for its deep color saturation and prominent yellow center.

I ordered it from Swann Island Dahlias and grew it in my garden this year. Delicate 3-inch wide blooms are perfect for small arrangements like the one below which includes Purple Dome aster (Symphyotrichum novae-angliae ‘Purple Dome’, USDA zones 3-8) and a variegated geranium.

Bigger dahlias need support to prevent flopping or falling over (when you plant the tubers, put the stakes in at the same time to ensure you don’t damage the clump later on). Tomato cages work fine but you’ll need tall stakes for the really big ones. You’ll also need string or a ball of twine to corral the stems as the season progresses. One of my plants of unknown origin grew about 7’ tall and Emory Paul, a dinnerplate type with deep pink double flowers, easily topped 6’ and needed help staying upright - it’s huge!

Above and below: A flower garden I designed for a client who wanted a lot of color and an extended bloom period. Positioning the dahlias on the edge of the path made them accessible for cutting. Multiple varieties grown together create an eye-catching display along with zinnias, nasturtium, daisies and phlox. This photo was taken on October 6th last year so you can see how good dahlias look with a fall perennial like aster ‘October Skies’ (Symphyotrichum oblongifolius ‘October Skies’, USDA zones 5-8) as foliage begins to peak in the background.

Pompom dahlias are smaller and easy to grow. I just ordered some heirloom types in a range of peach, coral, pink, and orange from Old House Gardens in Ann Arbor, MI to trial next year.

Below: The Bishop of Llandaff is an heirloom dahlia with deep red flowers and very dark leaves. I found these growing in a greenhouse border at Highclere Castle in the UK while touring the gardens there in August of 2019. This is a showstopper plant for sure!

Dahlias are prolific bloomers, making them one of the top cut flowers. They do need careful siting however, requiring good drainage and full sun. Soggy wet soils will lead to tuber rot. You can grow in containers too. Tubers are widely available; you’ll want to buy in late summer or early fall to be sure the ones you love are in stock. Shipment begins the following spring depending on where you live.

Ask your friends for divisions. I have several that came from other gardens and I share too; a single tuber will multiply underground during the growing season with fleshy roots that resemble a strange-looking octopus. Each clump can yield several new plants which originate from a growing tip called an eye. The eyes are what you look for when you’re wielding a sharp knife, cutting the clump into pieces to replant.

Every winter my basement holds several cardboard boxes of labelled dahlias stored in moist wood shavings which get opened in early May and divided into usable tubers with eyes (there are loads of resources available to learn how to dig, divide and store dahlias); divisions are then planted in early June when soil temperatures have warmed up in my northern Vermont garden.

All kinds of bees forage among the plants; as the weather cools they lose momentum and appear frozen on the nectar source, moving in slow motion as the sun wanes. Then the frost comes and the show is over with plants turning into a sodden black heap.

Below: This season I tried several new types. Loved this orange beauty called David Howard which has burgundy leaves and stems like the Bishop (foliage is great for adding depth to arrangements). I ordered it from White Flower Farm.

Below: This gorgeous one is called Creme de Cassis.

Below: Bride to Be is a classic white waterlily type that can cool down hot colors.

Cut plants (deadhead) to keep them producing. A couple dahlias and zinnias make a quick bouquet and always bring a smile when you give them away. Erin Benzakein’s latest book is a great resource - Discovering Dahlias: A Guide to Growing and Arranging Magnificent Blooms, available on the Floret Farm website or from your local bookstore. I put it on my holiday wishlist!

Color Focus: Orange

Orange is a standout in the garden. Why? It’s fun, it mixes with purples and blues well, and adding it to the vegetable garden or herbaceous border creates a bold focal point and helps move the eye along a busy composition.

Here’s a tulip called ‘Orange Princess’ which is a delight in late spring - look at the striping on the outer petals - such a delicious flame of warm colors!

‘Orange Princess’ is a late double flowering type that makes a beautiful cut flower. Blooms mid-May in my Vermont garden in USDA Zone 5.

One of my all-time favorites is the tender annual Mexican sunflower (Tithonia rotundifolia) which I sow directly in early June or transplant from the greenhouse or garden nursery. These are multi-branched plants that grow up to 6’ tall, lasting well until frost, drawing butterflies to their disc flowers and attracting a host of other pollinators. I usually grow in the vegetable garden along the split-rail fence; another good cut flower. Look for ‘Fiesta del Sol’ from Park Seed if you have limited space - it’s a compact cultivar that only grows to 30”. Tithonia makes a good combination with annual sunflowers and zinnias.

Below: Orange daylily cultivars are worth seeking out for the edges of beds and borders - easy to grow, they fall into the low maintenance category and will multiply over time making them a good investment.

Above: I really don’t know what type of daylily these are but I love their positioning along stairs at Longwood Gardens where their vibrancy helps define a transitional area. The luxuriant petals are slightly ruffled; even the new buds are interesting to look at.

Below: Don’t forget about heleniums (commonly called sneezeweed) - these North American plants are being hybridized with more and more available every year in various heights and bi-colors. Here are some I found in London at Royal Botanic Gardens Kew in the Double Herbaceous Border during the height of summer last year (mid-August).

Helenium cultivars I’ve grown include H. ‘Sahin’s Early Flowerer’, ‘Mardi Gras’, and ‘Moerheim Beauty’, a jazzy orange with splashes of yellow on its petals that grows to 36” tall.

Above: Marigolds are a staple in my garden and I adore their spicy scent and tough resilience - they’re one of the longest lasting annuals, blooming into November through light frosts. Deadhead to promote new growth. I usually plant these with the annual ‘Victoria’ sage for that orange-blue combination.

Below: Look at this structure I found at the Montreal Botanic Gardens - super fun! Someone had the brilliant idea of using shipping pallets to build a wall within a flower display. I especially love how the deep purple begonia foliage and the magenta and pink flowers look with the bright orange background.

And finally, a deciduous shrub with orange fruit - this is Ilex verticillata ‘Winter Gold’. It falls into the low maintenance category, suitable for wet or dry sites, but prefers sun and females must have a male winterberry planted nearby to fruit well (the genus is dioecious meaning there are male and female plants). Try putting one in your garden and snipping the branches for an indoor arrangement in the doldrums of February. Birds also love the berries.

Color Focus: Purple

Lavender, lilac, and violet all merge into purple and can carry over into blue, bringing calm and serenity. Again and again I’ll see purple as a focal point in gardens - it’s a very popular color choice and these hues mix well with everything .

Above: Salvia nemerosa ‘Caradonna’

Below: Everyone loves alliums (commonly called flowering onion). Easy to grow and fun for kids too.

Allium bulbs come in a variety of flower sizes and heights - plant them in the fall before frost. Most are purple but there are white ones too.

They make a good cut flower, draw in loads of bees, and bring a dash of whimsy. Keep in mind that after the flowers fade you’ll have strappy foliage which will need to slowly die back - if this is an issue you can treat them as annuals and dig up or locate the bulbs among hosta or other large leaved plants (which can effectively hide the yellowing leaves).

Above: Phlox subulata (moss phlox or creeping phlox) is useful along pathways or in rock gardens - one of the first perennials to bloom each spring. I adore the violet one which is native to Eastern and Central U.S., USDA Hardiness Zone 3-9.

Pansies come in the most luscious purples imaginable.

Above: Clematis vines also offer a wide range of purples and look great rambling up a white gate.

Clematis vines are fairly indestructible once you give them something to grow on (and shade at the root zone supposedly helps keep them happy). Do a Google image search with the words PURPLE CLEMATIS and look at all the wonderful choices. A friend swears by C. ‘Polish Spirit’ and so I’ve added one.

Above: Delphiniums are great verticals for the garden - tall spikes with multiple flowers ranging from lilac to deepest blue. The purples are simply irresistible and make a real statement - for many gardeners they’re the ultimate flower.

Below: Another great spike - butterfly bush (Buddleia davidii) is a magnet for monarchs and other insects. Look for ‘Dark Knight’ which is deep purple and give it winter protection if you garden in colder zones.

Below: Mexican verbena (Verbena bonariensis) is a self-sowing tender annual for us Northeast gardeners but what a beauty to weave through plantings. Tall airy wands pick up any wind and give a wonderful see-through quality to mixed borders.

Chelsea Flower Show

It’s a five-day theatre set piece that just keeps going, aisle after aisle of garden displays by the top designers in the world, set on the grounds of the Royal Hospital in the London borough of Chelsea - and I was there in the crowd for my third time on May 23, 2018 armed with my iPhone camera and water bottle. What a show! Everything you’d ever wanted to see is on view. Every year the big displays jostle for the RHS Gold medal with varying themes, all within the same alloted space - a long rectangle; smaller displays abound as well, some of these are targeted at city gardeners (small space design) while others showcase artistic elements, specialty growers, seed companies, and a host of consumer goods.

For a designer, RHS Chelsea is a feast. I’m still looking through my photos and notes, thinking about adding some new-found plant cultivar to my trial gardens or recommending some others to clients. If you’ve never been but would like to, visit the Royal Horticultural Society homepage for more information. I’ll be giving a slide talk of the Chelsea Flower Show through ACCESS CVU on March 21 from 6:30-8pm with highlights of my trip. Meanwhile here are some scenes and notes.

water

Every major display had some kind of water feature, the most dramatic was this cascade making a vertical sheet near a paved seating area surrounded by lush greenery for a tropical spa-like feel. The subdued color choices here also make it very modern - graphite, dove grey, chartreuse.

Creating a framework with vertical elements to enclose spaces is what makes a garden feel private. Many designs featured places to sit by yourself or entertain friends or even grow edibles in rooftop containers in the middle of the bustling urban experience with hedges of privet or hornbeam, pergolas made of steel, and lush plantings where foliage offers softness, complexity, and a scent. The RHS Gold Medal winner went to an arid garden designed by Sarah Price which had rust-colored plaster walls and xeric plants surrounding shallow pools.

RHS Gold Medal 2018 designed by Sarah Price

Design notes and sketches by Sarah Price

A Garden for Bees

I just gave a slide talk called Attracting Bees and Butterflies at the Horticulture, Education and Research Center at the University of Vermont in South Burlington which focused on the development of a Pollinator Garden which I’ve been involved in for a couple years. The talk showed the progress of this project from site work to installation and showed many of the beneficial plants that form the collection; afterward I led participants around the garden to look at both individual plants and at how they were arranged and grouped in the borders.

In late Fall the garden is at its peak with asters, anise hyssop, sweet coneflower, sedum, helenium, coneflower, goldenrod, and a variety of grasses which give bulk and texture to the borders.

This summer we had unusually hot weather and a long drought and it was evident which perennials suffered - those that prefer moist soils looked the worst (Joe Pye weed, swamp milkweed, monarda) - let’s see if they come back next spring.

The Pollinator Garden is a project of the Friends of the Horticulture Farm, a non-profit organization that helps support the collections at the HREC (known as the Hort. Farm). Since its redesign in 2014 I’ve been a volunteer consultant helping to manage the garden which was designed as an Outdoor Classroom. I love being part of the VT Master Gardener work days and teaching others about ecological landscaping. My good friend Sarah Salatino at Full Circle Gardens has continued to be a resource for this garden and has introduced me to many new native plants.

Fall asters are peaking now - and what a great source of food for butterflies and bees!