Early this spring I had the privilege of visiting the Desert Botanical Garden in Phoenix, Arizona, where I had my eyes opened to how many different varieties of agave there are. They reminded me of hostas back home.  Agave: loves dry heat and sun. Hosta: prefers shade and cooler temps. They are culturally opposite but have some things in common as a landscape plant. (For our Southwestern friends who think hosta is the agave of the Midwest... write your own article.)

They are both easy to care for, though agave may have an edge in that area. They do resemble each other somewhat and are both grown mainly for the look of their foliage. This foliage comes in all shapes, sizes and colors. Over 250 different varieties of agave are out there. Hostas on the other hand top 3000! Hostas come with many variations of the colors blue, green, gold, and white, with many combining these colors in variegated foliage. Agave have a similar palette, but also include some purple and pink and come in variegated varieties as well. When it comes to diversity of shape and textures, agave certainly seems to have the upper hand. Some varieties of agave reach sizes a hosta could only dream of.

The largest agave is Agave atrovirens. It can weigh a total of 2 metric tonnes. Each leaf can be over 14 feet long and weigh over one hundred pounds, and the flower stalk can grow over 40 feet tall. This may not be suitable as a landscape plant, but the Blue American is a gorgeous large landscape plant at 4-6 feet tall and 8-10 feet wide. These, along with other large varieties, can make the largest hosta feel inadequate. Leaves on agave can be wide or narrow, short or long, tightly packed or loose and open. The more you research the more amazed you become with the sheer variety

If I lived in more arid regions, I might miss certain plants, like hostas, but I could see myself joining the ranks of other obsessed agave collectors. Going to agave swaps across the southwest, scouring the internet for more varieties, drunk on my own home made mezcal. Deeper into the rabbit hole I would go, dabbling in cactus and succulents until I’m hooked on them as well. It wouldn't be long until I was involved in shady back alley deals trying to get my hands on the rarest varieties.

There would be an intervention most likely... to no avail.

 All photographs copyright David E. Baker.

…by planting native varieties and native cultivars.

Have you ever taken a moment to really appreciate our natural surroundings? Immersed as we are in smartphones and technology, I think we tend to forget to do this. I am often guilty myself, but I do enjoy walking through parks and woods and seeing the different oaks, maples, and other native species.

Our growing population has created a high demand for roads, parking lots, businesses, and housing. That land that was stripped to make room for a development contained its own habitat and ecosystem. Planting more native plants and native cultivars is a step to rebalancing the habitat that was lost.

What is a native plant?

This is a complicated question with much debate. Some believe it means plants that are untouched by man and naturally growing in the wild. You’ll encounter discussion on exactly where that “wild” needs to be to qualify as “native” for your particular project. Then there are native cultivars or “nativars”, which are selected, named varieties of native plants, with some improvement such as a more colorful bloom, nicer habit, or better disease resistance. It can be easier to source nativars than the original species, too as some plants do not lend themselves well to nursery production. You'll want to determine what the differences are from the original wild version to see if the improved one works in your particular project.

Benefits of planting more natives and nativars

• Once established they require very low maintenance.
• Often require less water.
• Attract and support native wildlife such as birds, butterflies, pollinators and more.
• Native plants help you use less fertilizers and pesticides.
• Already adapted to local climate conditions.

It is always a good idea to plant multiple different species and not all one variety. Doing this may prevent catastrophic loss in case a new disease or insect outbreak occurs, like the ongoing Emerald Ash Borer, Dogwood anthracnose, Boxwood blight, or Oak wilt situations.

Fun fact: A native oak tree supports over 500 species of caterpillar compared to the non-native ginkgo which supports only 5. Plant some oak, the songbirds will thank you. (Research by entomologist Doug Tallamy)

There are choices to make in any landscaping project. The microclimate can provide a place to start, then the considerations of general design and how much maintenance are one is willing to carry out, site traffic and usage, etc. Within the framework of your plans there are opportunities to go beyond visual enjoyment - your clients could actually taste the fruits of your labor!

Let’s begin by considering some plants that are readily available, or may already be in your design toolbox.

Aronia (Black chokeberry) is popular in Michigan landscapes. The white spring flowers turn into loads of nearly black berries which are eagerly eaten by birds. I encourage you to pick some for yourself - they may be exceedingly tart, but are tasty when added to sugary lemonade or made into jam. Consider Aronia m. ‘Viking’. Aside from the outstanding fall color, it's berries may be eaten right off the branch for an invigorating antioxidant-rich wallop to your tastebuds.

Agastache (Hyssop) is a perennial with aromatic leaves and flowers. There are blue-purple varieties and some newer cultivars in pink, coral, yellow or orange. Mix bruised leaves into tea for an alluring licorice flavor. Some varieties sway towards a mint flavor profile that I’ve enjoyed smashed into vanilla ice cream. Hyssop flowers make an enticing garnish in summer drinks.

Do you have dandelions in your lawn? Besides feeding honeybees, dandelions are a versatile culinary bonanza! Not only are the leaves an excellent salad green, but the flowers are edible, as well as the roots. Young flower petals have a honey-like flavor good in tea and jam, and the entire flower head may be sauteed in butter with garlic and eaten with a little salt on toast. Dandelion roots may be dried and brewed into a medicinal tea with many benefits.

Whenever discussing eating self-harvested plants safety must be mentioned. Always consider the plant and it’s surroundings. Pesticides, fertilizers, and any other runoff from the surrounding area will make it’s way onto and into the plants. Only consume a plant that you have properly identified and be sure to know the areas exposure to potential toxins.

If there is any doubt, do not consume it! 

These are some of my favorite edible landscape plants:

• Borage - Annual herb with star-shaped edible blue flowers.
• Daylily - Unopened flower buds can be eaten raw or cooked.
• Pansy - The flowers are often used as a salad or dessert garnish.
• Fruit trees and shrubs - Blueberries, apples, cherries, peaches, pears, etc.
• Honeyberry - (Lonicera caerulea) Large blue-black berries, used like blueberries.
• Lavender - Aromatic flowers and foliage with countless uses.

Perhaps the following recipe will inspire a patio conversation this summer.

Dandelion Wine

Boil 1 quart of rinsed dandelion flower petals in 1 gallon of water for 4 minutes, strain out and discard the petals. Allow the water to cool to under 100°f. Stir in 1 sliced orange, 1 sliced lemon, 8 cups of sugar (or 7 cups of honey), and 1 package of wine yeast and pour into sanitized plastic vessel, ideally fitted with a fermentation lock, but a towel and loose-fitted bucket lid will work. After 2 weeks decant or siphon into a secondary vessel or bottles and allow to age for at least 1 more week. Garnish with a freshly picked flower from your yard and enjoy the fruits of your labor.

If there is one plant every landscape should have, it is the peony. This handsome perennial is long lived and easy to grow, given a site with at least half a day of sun and decently well-draining soil. They are stunning focal points in mixed beds, or as the backbone of a perennial border, and belong in any style of garden from farmhouse to contemporary. Once I saw a row of peonies in full bloom running up a long driveway. I almost went off the road. The hard part is choosing which ones to plant. 

Peonies come in three types. The first, and earliest to bloom, are the woody-stemmed tree peonies (P. suffruticosa). The second are the fully herbaceous garden peonies (P. lactiflora, officinalis, and others), and the third are the intersectional peonies that are basically a cross between the two. Today's post is about the garden peony, the best known and easiest to find.

Let's dive in! Peonies have been cultivated for thousand of years and that means there are thousands of cultivars to choose from. Colors range from the purest bright white, to ivory, coral, pink - allllll the shades of pink - into fuchsia and finally, red. No matter which colors you choose, they all go together, so feel free to mix it up. The proper planting depth is key to getting flowers, so be sure to get those eyes no more than 1.5 - 2" deep. 

Peonies also come in a variety of different flower forms. My favorites are the wide open Single and Japanese forms, with bright showy centers, followed by the Anemone type that have a contrasting center fringed by wide petals. Other forms are Double, Semi-double, and Bomb. Many cultivars are fragrant, too. The earliest blooming ones kick off the season in mid-May, and by planting different cultivars you can go until late June. 

You may have heard that peonies, once planted, do not like to be moved. It is true that they are happy to stay in your garden for decades, but they can be transplanted successfully if you - like me - decide to move and can't bear to leave them behind. I've had my 'Sea Shell' peony for a good thirty years and she's doing great in her new garden.

Here in SE lower Michigan we have an amazing resource in the Nichols Arboretum Peony Garden (Ann Arbor), which has a massive collection of herbaceous peony, many of which are heirloom varieties. It has to be seen to be believed! Admission is free and the prime time to visit begins around Memorial Day weekend. You'll come away with a burning desire to plant peonies everywhere you can get a shovel in the ground.

• Nichols Arboretum Peony Collection Website
• American Peony Society - Herbaceous Peonies
• Peony Flower Types - American Peony Society (PDF)

All good things in life come from a bulb, isn't that how the saying goes? Okay, maybe not, but that is certainly true with Lilium! Planted in the spring (or fall), and returning every year, lily bulbs come in many different colors, and sometimes have a speckled or brush stroke pattern.

Lilium (Garden lilies) begin blooming in late spring, beginning with the Asiatic hybrids, and the distinctive fragrance of Oriental lilies on a summer breeze is sheer delight. With a little planning one can have lily in bloom for much of the season.

At Christensen’s Plant Center, we carry many lilies. One favorite is the Asiatic hybrid ‘Matrix’. This dwarf variety will only get 16” tall, and is a vibrant red with an orange brush mark in the center. We also carry tried-and-true Oriental Lily ‘Casa Blanca’ which gets 3-4’ tall. The highly fragrant pure white blooms are perfect for a classic look.

This year, we’re excited to offer three new Lilium combination pots. We’re loving the Asiatic Pot Lily Looks™ ‘Patio Sunrise Combo’ featuring yellow, pink, and orange dwarf varieties (14-16”). This will give you a fun mix that is perfect for a patio planter or cut flower bouquet.

The second is Asiatic Pot Lily Looks™ ‘Bloom Extensions™ Orange’. Lily flowers, though stunning, are usually short lived, but with Bloom Extensions™, you could get over 6 weeks of color. Two orange-flowering varieties, carefully selected to harmonize, have been potted together. The flowering times are offset, giving a seamless show of color. This is a great way to extend the display in your client’s landscape. This is an ultra dwarf combo reaching only 12-14”.

The third is Asiatic Pot Lily Looks™ ‘Bloom Extensions™ ‘Red & Yellow’. This stunning pairing of the yellow and red-speckled ‘Tiny Nugget’ (early, 14”) and the deep red ‘Tiny Rocket’ (later, 16”) is a real showstopper.

All the Lily Looks™ varieties have been selected for massive flower production, a short, compact habit, and suitability for container growing. Quantities are limited, and the grower has sold out - don't miss these! 

Whether you are looking for something unique or classic, our selection of Lilium has just what you are looking for.

Something so sinister, it will give you nightmares. Perennials and tulip bulbs will not be the only thing emerging from the ground this spring! I am talking about “Brood X” Cicadas. They are really not that scary, but their name makes them sound like something out of a horror movie.

The Brood X Cicada is a periodical Cicada. This fascinating insect spends nearly it’s entire life underground feeding on nutrients from the host tree’s roots. Once the soil warms up to 64 degrees - coming soon! - they will begin to surface from beneath the trees where their eggs were laid. Seventeen years ago, in 2004. There are different kinds of Cicada with different maturation cycles but just one that takes this long, and it is only found in the Eastern United States. The reason there are so many all at once (Millions! Billions?) is probably an adaptation to foil predators – there are simply too many to all be eaten.

You may see their exoskeletons on the side of your house or on the trees, left behind as the winged adult molts. There are annual Cicada that emerge every year in much lower numbers, and the low-pitched buzzing they make is a sound of summer. But if you think the yearly Cicada is loud, wait until this year! In Michigan, Hillsdale and Washtenaw Counties saw the largest population so we are in prime position to witness this phenomenon.

The red-eyed creatures may look intimidating but are harmless to pets and humans. Some areas with large pockets of these insects may see broken branches from younger, fragile trees or plants due to the sheer numbers of Cicadas. Not to be alarmed though, Cicadas cause minimal damage. Spending all but 4-5 weeks of their lives underground, they move through the soil and naturally help aerate it. After they arise from their chambers and molt, they have but one goal: to mate. That deafening sound is the call of the male Cicada. Once mated the female has a razor-sharp appendage to cut a V shaped slice into branches where she will deposit her fertilized eggs. The eggs take about a month to hatch into nymphs and fall from the tree to burrow and start the next 17-year cycle.

Ok, so maybe not so sinister or evil, but intriguing instead. Let us try to appreciate them for their short visit and loud noises after the 17-year long journey they have been on.

Check out these links for more information:

• When will Cicadas emerge in 2021? - USA Today
• Cicada fact sheet - Maryland Dept of Ag.

In 1892 a German physician, Richard Pfeiffer, believed he discovered the culprit that caused the Influenza Epidemic of 1889-90. An Infuenza bacillus became the focus of attention in the fight against the Spanish Influenza of 1918-19. Vaccines were being developed just as they had 100 years earlier for smallpox. Medicine had already conquered rabies, tetanus, anthrax and cholera before the new century. But they would prove ineffective and the Great Pandemic would simply fade away.

In 1933 an article “Failure of a Bacterial Vaccine...Against Influenza” announced the discovery of a new pathogen, a virus, Influenza A. Five years later Doctors Salk and Francis would develop the first vaccine for Influenza A and B. But the H1N1 virus has not faded away. It was believed to have caused the epidemics of 1848-9 and 1889-90. In my lifetime it has resurrected in 1957, 1968, and again in 2009. These pathogens are genetic strands looking for a way to replicate. Unlike bacterium which can reproduce outside or inside another living organism a virus can only replicate in a host living cell. For this reason viruses actually become less deadly as they mutate. Without a host their fate is in jeopardy as well.

Viruses are spread initially and primarily by mosquitoes, ticks, and sand-flies. When conditions for these arthropods are good they create an environment for the spread of these pathogens to plants, animals, and humans. Just like the mistakes of the past many plants problems have been attributed to bacterium or fungal disease, when, in fact, there are many viruses that can affect plants and threaten our food supply.

Many of these viruses in plants manifest as mosaics. Cucumber Mosaic Virus (CMV), zucchini (CYMV), and tobacco (TMV) are just a few of the predominate. TMV, in particular, hitchhikes on aphids and other insects; it affects many of the Solanaceae family, including tomatoes, peppers, and potatoes. Mosaics can show up as mottlings, variegations, mutilated leaves, and more. What is significant is these disfigurements are not caused by the virus but by the plants fighting off the virus. A plant’s own genetic material will recognize the intruder and try to cut off its path with its enzymes and other defense mechanisms, called the Argonaut complex. It is this shotgun approach that does damage, but plants can win in this process. Science, as in the study of viruses that affect humans, must realize the most effective and least destructive complex. The result is treatments such as vaccines. In plants they are sprayed or rubbed onto the foliage ( probably no needles).

In the landscape industry, we have had two recent incidents of viruses affecting planting material. In 1996 Hosta Virus X (HVX) was recognized. It is a sap to sap vehicle that spreads this pathogen. In the beginning many of the mutations to hostas were thought beautiful and desirable. But the degradation and spread by mere proximity and handling brought the problem to a head. Culling of affected plants, spacing of plants, and more recently testing for virus at plant production sources have all but eliminated the problem.

In 2011 the greenhouse growers were faced with Impatiens Necrotic Spot Virus (INSV). The result was a loss of cash crop for several years as growers sought out strains resistant to this virus. Noteworthy is the fact that many viruses in plants are actually passed on by seed.

Although genetic mapping is still relatively new it is beyond hopeful that science and medicine will be able to give us the tools to fight these pathogens and protect our food supply.

Do you buy a fresh Christmas tree? I do. Still a traditionalist. December 2020 was a "stay at home" year which meant Christmas tree shopping. Boy did I get a surprise, not just sticker shock - but finally on our third stop I found a tree “I could live with”. I tell this story because the scarcity of all evergreens is scary. Not just cute sheared Christmas trees, but 6’, 7’, 8’, and up, Colorados, Black Hills, even Chamys (can’t spell that word – it would make a great password). Soon Arborvitae? Then…? Get them as soon as you can and lock them up!

Unfortunately plant material in general is going to be scarce. 2020 was a boom year for “gen-whatever” to plant or get planted for yard fun. 2021 is going to be identical – just much harder. No, not harder – “more interesting”, as Tim would say. You might want to come to pick plants with a couple of options. Knowing which is more important: size? color? or location. If your customer really has to have “THAT” plant make sure they know, they may have to wait for “THAT” plant to grow up a little!

We are prepared!! We are working hard to make sure your job is easier. Remember: dull is well, just dull, but “more interesting” has sparkle.

A recent article by my coworker Matt reminded me of this old saying. It’s born of the experiences of many rock and perennial gardeners. Throughout the years gardeners have collected and experimented with plants, looking for ways to use plants not necessarily accustomed to their soil type or zone. Their answer, in part, was raised rock gardens. Not only aesthetically pleasing, this approach created mini-climates in small spaces much in the same way mountain ranges create dramatic changes in flora from ridge to ridge. Lush forests give way to arid deserts on opposing side of the same mountains.

Rocks and raised beds give plants good drainage. Many perennials in the North die, not from cold, but from excessively wet ground conditions. Perennials such as Dianthus, Lavandula, Gaura, Thymus, et al. thrive in their first plantings only to rot during their juvenile winters. Perennials with long tap-like roots such as Lupines, Hollyhock, Foxglove to name a few die from crown rot due to excessive surface moisture. The fence post problem – solid above and below the ground but rots off right at ground level.

Ground-covering plants like Sedums, Ajugas, Thymus run along filling the crevices, encouraged by the cool, moist conditions. The seed of many annuals and perennials find some of these same places to spend their first winter, where they experience death and rebirth in the stratifying process. A true, natural nursery.

Rocks help ease the stress of extreme temperature change. In the summer they create cool, moist conditions on their down side. In the winter they warm with the sun, giving roots some protection against the cold. Gardeners were often able to include plants that were a zone less hardy. This also works for woody ornamentals that are usually considered sub-shrubs such as Buddleia, Caryopteris, Callicarpa, Hypericum, Crape Myrtle, and more. These types of woodies experience varying degrees of dieback but recover well from roots and heavier wood. Even just tucking hand-sized rocks around the base of perennials and shrubs can give protection and anchor the late-planted.

So when it comes to planting, if you’re ever in doubt, just go get one.

Photos © Holly Christensen, except mountain scene (Storyblocks)

In recent years, I’ve often heard that we should leave the first round of dandelions to grow and flourish for the benefit of early food for bees. You don’t need to tell me not to mow… done! That’s an easy way to help out our little winged friends.

As the movement to promote bees increases, it’s a good idea to have a pollinator plan ready for customers interested in this topical form of conservation.

For starters, since honeybees begin foraging when temperatures approach 50°, your plan needs to begin early. Minor bulbs such as Crocus, Winter Aconite, Snowdrops and Chionodoxa are valuable food sources on those first warm spring days when little is in flower. A few weeks later the Red Maples pitch in, followed by showy spring bloomers like Forsythia, Redbud, Amelanchier and Magnolia.

Mid-to-late spring has no shortage of excellent choices, as most of our ornamentals bloom then. As things taper off into summer, Monarda, Dianthus, and Echinacea offer long blooming periods that keep the bees happy. Late summer is more challenging but Rose of Sharon and Caryopteris are two species that bloom almost into autumn.

At the tail end of the season plants like Aster, Helianthus and Sedum are excellent fall bloomers. The beginning and end of the season are the most critical, as there are fewer food sources than during the peak of the season. If you’ve incorporated annuals into your design so much the better as they will go until either killed by frost or removed.