How To Keep Your Potted Plants In Shape All Summer

It’s that time of year again when we stock up on flowers for our containers. And the plants always start out looking great. But in no time, the blooms fade and the stems turn long and leggy. As a landscape designer, this is the most common question I get: How do I keep my potted plants in shape all summer?

The Three-Step Rule

There are three key steps to remember when caring for potted plants. In order to grow successfully in containers, they require:

Would you go a day without water or a month without food? Your flowers depend on you to provide them with all they need. Follow these steps and you’ll have blooms all summer.

Water, Water and then Water Again

Annuals are called annuals for a reason. They have no permanent root system. In order to survive, they need a regular supply of water. In fact, shallow roots, which have limited capacity to store water, require water daily. Don’t let anyone tell you otherwise! As soon as the top of the soil dries out, potted flowers do, too.

Annuals have shallow roots that require water daily

When watering your potted plants, water at the soil level to avoid wetting the leaves. Wet foliage can encourage fungus to develop. A good rule of thumb is to water at the soil level until excess water seeps out of the pot. That way, you’ll know you’ve completely moistened all of the potting mix. 

Feed For More Blooms

Even though potting mixes come packed with ingredients, containers quickly lose nutrients to hungry plants and frequent watering. As a result, potted plants need to be fed so they can keep on growing. I feed my flowers twice a month, from spring to fall, with a water soluble fertilizer.

That said, it’s important not to overdo things. Too much fertilizer will produce lots of lush foliage, but fewer blooms.

Groom To Keep The Shape

A great haircut can be transformative. And after just a few weeks in a container, flowers can start looking shaggy. You can control for this with proper grooming. 

Groom your plants by regularly deadheading faded flowers and pruning leggy stems. Make sure to pinch or snip back stems to an intersecting branch at a 45 degree angle. This key task will help maintain the form of your plants and stimulate them to keep on blooming.

Below are three popular potted plants and how to keep them in shape all summer.

Geraniums

Though grown as an annual in most areas, the common geranium is actually a ‘tender perennial’, meaning it won’t survive cold temperatures outdoors. While it’s tempting to buy this beautiful plant in early spring, it’s usually best to hold off until around Mother’s Day when there’s less risk of it getting zapped by frost.

A healthy geranium has a few central stems and lots of side shoots (which is the optimum structure for a strong plant that will produce lots of flowers.) To keep your geranium looking good, prune back the central stems by about a third a week or two after potting it. This will encourage more side shoots to develop and maintain the plant’s fullness.

As the season progresses, regularly pinch the side branches of your geranium down to the angle where the branches fork. This will prevent the plant from becoming leggy. And deadhead (pinch at the base) all flower stems as soon as they have faded. This will encourage new flowering.

Petunias

Petunias quickly become leggy without some prudent intervention. They can also quit blooming almost entirely after an initial colorful flush. No worries, though. With proper watering, feeding and grooming, you can keep your petunias looking good all summer.

Like all flowers, petunias must be regularly deadheaded to encourage new blooms. However, unlike most flowers, removing the dead blooms accomplishes only part of the job. That’s because at the base of the petunia flower there is a small, nugget-sized pod that produces seeds. If you leave the pod on the plant, the petunia will stop blooming.

So in order to get your petunia to produce more flowers, remove the entire flower stem.

Deadheading the flowers (with stems) on a regular basis will keep your petunias blooming: however, it won’t solve the leggy problem. To control legginess, prune your plant every week, cutting back about a third of the petunia. You can do this by pinching branches selectively or grabbing clumps and shearing them off. Each week, cut the plant back by another third. Rejuvenating petunias in this way will encourage new stems and blooms to sprout from the interior branches.

Begonias

These bright-colored flowers require less care than geraniums or petunias, but still need regular pruning to maintain their compact shape. The same goes for the indoor varieties, by the way.

To keep your begonias looking their best, prune the outer branches (called canes) harder than the interior ones, pinching back the growing tips of new shoots to encourage new stems to develop. Prune the interior canes at varied heights and prune the outer canes at the lowest. This will encourage new growth at the base of the plant and prevent it from looking bare at the bottom.

If your begonia has lost all of its lower leaves, you can cut it back all the way to the soil. This will force the plant to send up new shoots. You can then continue pinching new stems as they grow until you achieve the desired shape and fullness.

A note on begonias, both indoors and out. They don’t like to be overwatered.

 

How To Create Winter Interest In The Garden

I grew up near Chadd’s Ford, Pennsylvania in the heart of the Brandywine Valley. The painter, Andrew Wyeth, drew inspiration from this place, beautifully capturing the winter landscape in a moody mix of soft browns and grays. My growing years were painted in the same palette, enhanced by the crisp outline of bare branches against a snowy white sky. Nature sure knew how to create a lot of winter interest. Continue reading

True Blue Flowers: 12 Of The Best And Brightest

For centuries, people have searched for a true blue flower. Elusive and rare, it is seldom found in nature. Or, to put it another way, it is rarely perceived in nature. It all has to do with what each of us sees as blue.

To find out why, I signed up for an on-line lecture given by Brandon George, a grad student working at Cornell Botanic Gardens. His research not only produced a great list of blue flowers, but also shed some (hint) light on the issue.

WHAT CONSTITUTES BLUE

So why is blue so rare in the plant world? For starters, I’ll ask you to refer to the color wheel below.

Blue is a primary color. On the visible color spectrum, it is located between green and violet. But that’s where things get murky. Take a look at the wheel. Some blues tend towards green, while others tend towards violet. Do all of these colors merit the name blue?

At the moment, the Royal Horticultural Society (RHS) is the go-to authority. The RHS Colour Chart, created in 1966,  contains 920 pigments that can be matched precisely to flowers, fruits and other plants. Over the decades, it has become the primary means by which growers and horticulturalists communicate about colors around the world.  

Still, the color chart doesn’t explain why a true, pure blue remains so elusive. And here’s why. Though blue is a prominent color on earth, it is rarely produced in nature. In fact, of all the 280,000 known species of flowering plants, only 10 percent are blue.

HOW PLANTS PRODUCE BLUE

It turns out that plants aren’t born blue. Instead, like artists, they must mix naturally-occurring pigments to achieve their blue hue. The most common of these pigments are called anthocyanins. However, anthocyanins change their color depending on soil pH.

Hydrangea macrophylla ‘Nikko Blue’

In fact, just the tiniest tweak of metal ions in the soil can result in the same plant producing entirely different shades of blue. (Think blue hydrangeas, which are produced by adding acid to the soil.) Finding a true blue flower is really hard indeed.

WHEN PURPLE LOOKS BLUE

Even then, some of us may still see purple as blue.  Deutan Color Blindness (do-tan) is an anomaly of the ‘M’ cone (Medium Wavelength Light) in which spectral sensitivity is shifted toward longer wavelengths. If you have it, you may experience confusion between colors such as purple and blue. Take a look at the photo below. Do you see purple and blue or just blue?

Photo credit/enchroma.com

TRUE BLUE PRETENDERS

Nowadays, blue flowers are highly prized. As a result, growers are introducing more and more plants that are labelled as blue. But beware – many are not truly blue! To differentiate among cultivars, horticulturalists now use the term ‘true blue’ to indicate a more true blue pigment.

Take, for instance, the hardy geranium ‘Rozanne’, a popular choice for the perennial garden. Some growers list it as violet, others lists it as blue. How do you perceive it? To my eye, it tends towards purple. While my client sees it as blue.

Hardy geranium ‘Rozanne’/Photo: anniesannuals.com

And have you ever wondered why the same blue plant can look entirely different across catalogs? Just because a plant has blue in its name doesn’t necessarily mean it’s blue. Some growers manipulate photos to make plants appear more blue. Still others use tricks of light. If you can’t see the plant in person, George recommends consulting user uploads rather than seller photos to get a better perspective on a plant’s true color.

TRUE BLUE FLOWERS

There is one plant family that typically produces the truest blue flowers in nature. Boraginaceae, also known as the forget-me-not family, includes more than 27,000 species. The plants of this family are frequently hairy and include such garden ornamentals as Virginia bluebell (Mertensia virginica), Lungwort (Pulmonaria), Forget-Me-Not (Myosotis)and Siberian Bugloss (Brunnera macrophylla). Horticulturalists agree that these are indisputable blues.

Virginia bluebells

Other indisputable blue flowers include Grape hyacinth (Muscari), Siberian squill (Scilla siberica) and Blue Drumstick allium (Azure allium), in addition to pH-sensitive Hydrangea macrophyllaNikko Blue‘, which in acidic soil (a pH below 6) will turn blue. 

Blue Drumstick, Allium caeruleum

And don’t overlook the sky blue flowers of Siberian larkspur (Delphinium grandiflorum), and Hardy plumbago (Plumbago cerastostigma), which are all great additions to the spring/summer border.

TRUE BLUE ANNUALS

Perennials not your thing? There are some great almost-blue annuals. Evolvulus ‘Blue My Mind’ is a dwarf morning glory with fuzzy, silver-green foliage. It looks great in containers or windowboxes, where it will happily trail over the edge.

Other great true-blue annuals include Cape Plumbago (Plumbago auriculata), a very light blue, Love-In-A-Mist (Nigella), and Gentian sage (Salvia patens), a tender perennial that has the deepest blue flowers you’ll find.

Gentian sage, Salvia patens

DESIGNING WITH BLUE

When working with blue, remember it is considered a cool color, so it will recede into the landscape. Consider bringing it forward to enjoy it and plant cultivars in mass for a stronger effect.

But a word of caution. Placing a lot of different ‘blues’ together will often cause some to look bluer than others (see below). To prevent this from happening, separate them out and plant them instead next to contrasting colors (such as orange or yellow), which will give the illusion of a brighter blue.

Blue or purple? Delphiniums growing in Dalat, Vietnam

 

Plant Trends 2021: What’s New for Spring

Even in the world of gardening, it’s important to stay ahead of the curve. And to do so, one need look no further than Kathy Jentz. As editor and publisher of Washington Gardener Magazine, her depth of plant knowledge is incredible. Recently I attended her talk on the biggest plant trends for 2021 during which she highlighted some key things to look out for this spring. 

SIMPLIFICATION IS KEY

These days, the overriding theme is simplification. Unless you’re up for the task, who wants to buy a plant that needs weekly spraying or constant pruning to keep it in bounds? Jentz says consumers want their plants to bloom longer, have greater disease resistance and be able to stand up to drought and other factors due to climate change. And growers are rising to the challenge.

Indeed, growers are answering the call by engaging in greater hybridization to propagate desirable characteristics such as color, size and vigor. Here are four plant trends Jentz says are rocking today’s industry. 

TINY PLANT TREND

Plants are scaling down – think dwarf evergreens, smaller shrubs, and more compact and manageable perennial species. Not only are these new hybrids better suited for smaller gardens, but they also require less maintenance while flowering longer. (And for growers, they look better on the shelves.) Teeny tiny houseplants like terrariums plants and tiny succulents are also gaining in popularity.

Teeny tiny cacti getting ready for market

DAY LENGTH NEUTRAL PLANTS

Day length neutral (D/L) refers to plants that flower independent of day length. In other words, unlike short-day plants that flower in spring and long-day plants that flower in summer, these plants will flower all season long. That means that if you want to grow sunflowers in early spring or late fall when days are shorter, all you need to do is choose a day length neutral variety. 

plant trends D/L neutral sunflowers

D/L neutral sunflowers extend the growing season

ENVIRONMENTAL SUITABILITY

These days, you can’t be too sure of the environment. So growers are responding by introducing plants that exhibit higher degrees of drought tolerance and disease resistance. Some varieties have even been bred to stand up to wind, wet weather and road salt, providing more options for the home gardener.

monarda didyma

Many new monarda hybrids exhibit greater disease resistance

NEW BRANDING OF FRUITS AND VEGGIES

For those of us who dislike having to cut up an entire melon to consume only a few pieces, say hello to personal snack-able fruits and veggies. Helo Clementines and Hello Melon are two great examples of this 2021 plant trend. Personal-sized fruits and veggies make it easier for consumers to eat healthy food with less wastage. Now you really can have your melon and eat it too.

Hello Melon’s small size makes snacking easy

TEN TRENDING PLANTS FOR 2021

Ready to make your list? Here are some trending plants Jentz profiled for 2021 that I’ll be looking for at the nursery. 

Whispurr Pink Nepeta – This soft pink hybrid is a little bit taller than ‘Walker’s Low’ and it blooms all summer.

Whispurr Pink Nepeta/Photo: darwinperennials.com

Panicum virgatum ‘Purple Tears’ – An introduction from Pete Oudolf who discovered this native species in a nursery plot in the Netherlands, ‘Purple Tears’ switchgrass produces soft gray flowering spikes followed by striking purple seed heads. Narrow and upright, it grows to about 4′. Available through Hoffman Nursery of North Carolina. 

Purple Tears switchgrass/Photo: Hoffman Nursery

Begonia Lunar Lights ‘Silver Moon’  Forest green leaves flecked with silver and mint green make this perennial a stand-out in the shade garden. Available through Plants Nouveau. 

Begonia Lunar Light ‘Silver Moon’/Photo: Plants Nouveau

Swan Queen Gardenia – Bred to be hardy in our region (Zone 7), this variety with glossy evergreen leaves and double white blooms can stay outdoors all winter. It also is resistant to white fly and other diseases that usually affect this plant. Available through most area nurseries. 

Swan Queen Gardenia/Photo: monrovia.com

Brunnera ‘Alexandria’ – Not to be confused with the green and white variety ‘Alexander the Great’, ‘Alexandria’ looks like a silver mirror in the garden and has the biggest leaves yet of the species. Tiny clusters of sky-blue flowers float above the iridescent foliage in early spring. 

Brunnera ‘Alexandria’/Photo: monrovia.com

Forsythia ‘Believe it or Not’ is a one-of-a kind variety developed from a plant found at McCorkle Nurseries Inc in Dearing, Georgia. In addition to golden flowers, it has variegated gold foliage which means you can enjoy yellow color from spring until fall. A mid-sized shrub that thrives in sun to part shade from the Gardener’s Confidence Collection

Yellow leaves of Forsythia Believe It Or Not/Photo: The Gardener’s Confidence Collection

Celosia Kelos ‘Candela Pink’ – If you like things hot, this plant is for you.  The 2021 All-America Selections (AAS) Flower Winner, its bright pink blooms prompted one judge to name it the ‘Energizer Bunny.’ This selection is bred to keep its color all season long and it also makes an excellent dried flower. 

Celosia Kelos ‘Candela Pink’/Photo: all-americaselections.org

Ready-To-Grow Clematis – Clematis has a reputation for being difficult. But these new varieties introduced by Spring Hill Nursery are out to change that opinion. Their stronger root systems reduce transplant shock; they can be popped right into the ground. And they offer improved flower production. Check out ‘Chloe’, a non-vining bush-like variety with purple-blue flowers. 

Clematis ‘Chloé’ available through Spring Hill Nursery

Coleus Main Street Beale Street A spectacular new variety that holds its deep red color all season long, this coleus won’t fade or bleach over the summer. It forms a compact 2 ½’ x 3’ ball, and since its flowers don’t appear until very late in the season, there’s no need to deadhead. Available through Premier Growers Inc. 

Coleus Main Street Beale Street/Photo: premiergrowersinc.com

Petite Knock Out Rose – This variety is the first-ever miniature version of the popular Knock Out Rose series. Topping out at just 18″ tall, it exhibits the same flower power and easy care as the rest of the species.

Petite Knock Out Rose/Photo: knockoutroses.com

Marigold Big Duck Yellow Huge, double-flower balls make this semi-dwarf variety a stand-out. Also available in orange, Big Ducks spread like a carpet and are extremely heat tolerant. Available through ameriseed.net.

Big Duck Yellow/Photo: ameriseed.net

Poppy ‘Amazing Grey’ This showstopper has lavender grey tissue paper-like petals with a pinky-red center. Some flowers also have a white edge. En masse, the double and single blooms look like grey clouds hovering in the garden. Available through Wild Seed Farms.

Amazing Grey Poppy/Photo: wildseedfarms.com

Author’s note: All links to seed and plant purveyors are unpaid and reflect only my recommendations. 

Cover photo of Clematis florida Alba Plena courtesy shutterstock.com.

 

There Are No Dead Ends In The Corn Maze

I’ve always been fascinated by mazes. And the corn maze is my number one favorite. Far less predictable than a typical hedge maze, the corn maze changes each year, adapting its complex network of passages to the whims of its creator. The corn maze challenges us to draw upon the very best of our navigational skills to face the unexpected. Not unlike daily life, I’d say. Continue reading