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)

It’s not always all grinding and going at Christensen’s Plant Center, sometimes we crew members get to stop and smell the flowers - and during the summer - find some of them crawling with beautiful monarch caterpillars.

Monarchs are not yet an endangered species, but they and their migration are being threatened and need protecting. So at Christensen’s we started rounding up our Monarch caterpillars and putting them into mesh butterfly cages with a milkweed plant for food. Monarchs feed solely on Asclepias, using the toxins in the milkweed to make themselves very unpleasant to predators. Animals and birds who eat a Monarch caterpillar or butterfly get pretty sick from it and won't eat another. There are still a lot of losses, though, so raising and releasing them really helps boost their numbers.

They are voracious feeders, so we check them daily, replacing the host plant as needed. Once they’re nice and fat, they’ll eventually J-up (they hang, head down, in a ‘J’ shape) and morph into a chrysalis within hours. Then after about 10 days, you’ll have a beautiful Monarch butterfly. Easy, right? One day when we came into work, we had three hatched and ready to take off!

Be careful of escapees though - we had one little guy escape and he ended up morphing into his chrysalis under the table. If you have a cage with a zipper, make sure there’s no one by it when you unzip it or a caterpillar could get caught in it (yes, sadly we learned that one from personal experience). Also beware of invaders: spiders and flies love to sneak in which can be dangerous for the butterflies-in-training! Other predators include wasps, assassin bugs, ants, toads, and even mice.

Plants like Allium, Buddleia, and Liatris seem to be swarming with Monarch butterflies this time of year. Monarchs are an important pollinator for many wildflowers. Providing a safe place for Monarchs to grow and multiply is a rewarding and beautiful experience.

See here for more about growing milkweed: Milkweed for Monarchs - Michigan DNR​

You may nave noticed something different in our perennial pots recently. Covering the soil of some of the varieties we grow are tiny rice hulls. Sounds delicious, right? No, it's not the starchy side dish.

Rice hulls are a sustainable soil amendment with many advantages. Here at Christensen’s Plant Center rice hulls are used mostly as a top dress to prevent weeds. Our perennial production department applies them at the time of potting. Used properly, they can help control a weed problem before it even begins. If you can manage to get more rice hulls in the pot than on your person, these can be very effective.

Rice hulls can also be used in the landscape. Mixed into the top 6-12” of your garden or planting beds, the advantages include better drainage, water holding capacity, and soil aeration. And for all of you environmentalists out there, rice hulls are 100% organic and biodegradable.

As a top dress, rice hulls are great for holding moisture and preventing weeds, but there are a few downsides. THOSE THINGS ARE A MESS! Once you open up the bale, you will find it in every pocket and every shoe of those around it. Also not the best thing to use on a windy day... We've found that the most effective plants to use it on have been hosta and daylily.

Sometimes the rice hulls work a little TOO well. With plants that cannot handle a wet crown, rice hulls should not be used. Since rice hulls are to be applied ½-1” thick, that can be too much moisture. For plants like sedum, rice hulls are not recommended. 

Rice hulls are a cost effective, easy way to maintain plant moisture and keep away weeds. Just not the best to have for lunch. 

...and I don't mean cider or donuts. No, it's COLOR TIME! 

Mums. Burning bush. Maple trees! You can probably name a dozen fall color plants without even thinking about it. But what about choosing from some of the lesser-known plants that also shine every autumn? Here are my top ten favorite fall color plants that may not be on your radar.

• Hydrangea quercifolia and cultivars: The large, rough-textured leaves are especially striking as they turn shades of red and purple every fall.
• Viburnum x juddii: Beloved for it's sweetly-scented spring flowers, this medium-sized shrub has great burgundy-purple fall color accented by blue to black berries.

• Itea virginica cultivars: This medium-sized native shrub deserves to be planted more often. The orange, red and burgundy fall color is outstanding and is extremely long lasting.
• Epimedium cultivars: An underused perennial tolerant of dry shade that gets brilliant red to purple fall colors.
• Amsonia hubrectii: This North American native perennial grows to about 3x3'. The fine, feathery foliage turns a striking golden-yellow in the fall.
• Clethra alnifolia ‘Hummingbird’: Usually planted for the amazingly fragrant flower spikes in mid-to-late summer, this smallish shrub turns a gorgeous golden yellow each fall.

• Fothergilla ‘Mount Airy’: This is a handsome 3-5’ shrub that gets wonderful fall color in hues of red-purple, orange and yellow.
• Amelanchier: OK, so this one is not that obscure but it has to be in my top ten.
• Vaccinium hybrids: These ericaceous shrubs (best known are blueberries) will surprise you with their beautiful red-orange fall color.
• Panicum virgatum cultivars: ‘Shenandoah’ and ‘Hot Rod’ are two that turn beautiful red or burgundy.

Horticulturally speaking, the color blue is rare. So rare, that many of the flowers we call "blue" are in fact... purple. Blue iris? Purple. Blue roses? HA! Purple - and weak at that. Syringa, Campanula, Lobelia, Hyacinth, Baptisia... all have varieties CALLED blue, but they are... purple. I found this quite confusing when I started in the nursery business. Apparently we gardeners are DESPERATE for blue in the garden and we will call anything close "blue".

This tendency extends to foliage as well - blue spruce, blue juniper, and blue hosta, are all rather more silvery than blue, with the added insult of the color wearing off with weather and time! I still chuckle about the customer I had on the retail lot one day, who accused us of spray-painting the 'Moerheim' spruce because, "Look! It rubs off!" There wasn't much I could say because he was right, it did.

There ARE a few truly blue flowers we can grow in Michigan. Amsonia, Delphinium, Virginia Bluebells, the annual 'Black and Blue' Salvia, Forget-me-nots, Sisyrinchium, and Ceratostigma all have excellent blue flowers. Scilla siberica is a minor bulb that naturalizes and can give you an ocean of blue flowers every spring. Chionodoxa's pretty good, too.

In shrubs you can try Caryopteris - wait, that one's a bit on the purple side - heck, it's barely a shrub, more like a woody perennial. Hmmmm. Hibiscus 'Blue Chiffon' is pretty blue. Almost. OKAY, OKAY, FINE. You want blue? You'd best be planting Hydrangea. The old favorite, 'Nikko Blue' has been surpassed by newer cultivars like Nantucket Blue™ and The Endless Summer® line, with the original Endless Summer®, Twist-n-Shout®, and BloomStruck®  all of which bloom on both old and new wood. These plants can be coaxed into producing nice blue blooms with the proper soil pH.

So you do have some options. And take those photos of bright blue-flowering plants on Pinterest with a grain of salt. Most of them are Photoshop. Or perhaps dyed like those poor Phalenopsis orchids at the grocery store.