Spring is here, and with it comes a fresh start to another busy season of designing and building beautiful outdoor spaces. As the ground thaws and job sites come back to life, let’s get back to the basics—the foundation of every great paver patio.

That foundation begins with limestone aggregate.

Limestone has been a fundamental building material for centuries, prized for its durability and versatility. The limestone we use today took hundreds of millions of years to form. Once part of an ancient tropical sea, limestone is composed largely of calcium carbonate from marine organisms like corals and shellfish. Over time, layers of these skeletal remains compacted into the dense, sedimentary rock we rely on today.

Remarkably, many limestone aggregates still bear the imprints of their ancient origins—fossilized remnants of prehistoric marine life are frequently visible within the stone, offering tangible connections to Earth's distant past long before humans first learned to craft with stone.

Thornton Quarry: A Massive Source of Limestone

Thornton Quarry, located just south of Chicago, is one of the largest limestone quarries in the world. Spanning 1.5 miles long, a half-mile wide, and reaching depths of 450 feet. The site has been in operation since the 1800s. It supplies crushed limestone for road construction, concrete production, and hardscape base material. The quarry is also notable for its role in flood control, as part of the Chicago Deep Tunnel project. The northern section of the quarry has been repurposed as a reservoir capable of holding nearly 8 billion gallons of stormwater, helping prevent urban flooding. With its vast limestone reserves and dual role in infrastructure and environmental management, Thornton Quarry is both an industrial powerhouse and a critical component of regional water management.

From Quarry to Job Site: The Journey of Limestone Aggregate

The extraction and processing of limestone is a monumental industrial endeavor that combines raw power with precision engineering. Modern quarrying operations employ specialized excavators and blasting techniques to dislodge massive sections of limestone from exposed bedrock formations. These colossal fragments—sometimes weighing several tons each—are transported via heavy-duty articulated dump trucks capable of hauling 100-400 tons per load to primary crushing facilities.

The transformation from raw stone to construction-grade aggregate involves a sophisticated multi-stage crushing process. Initial jaw crushers reduce limestone boulders to manageable sizes, followed by cone or impact crushers that further refine the material. A complex network of vibrating screens—some spanning hundreds of feet across processing facilities—carefully sorts the crushed stone into precisely-calibrated size gradations. Quality control measures throughout this meticulous journey ensure the final product has consistent compaction rates, optimal angularity for interlocking strength, and appropriate levels of limestone fines for each specific application.

Christensen’s stocks a variety of limestone aggregates tailored for hardscape applications, including:

• 21AA Limestone – A mix of fines and larger crushed stone, designed for high compaction. Ideal for structural base layers beneath pavers, driveways, and retaining walls, ensuring long-term stability and load-bearing strength.
• 6A Limestone – A clean, angular stone ideal for drainage applications, backfill behind retaining walls, and permeable base layers. Its uniform size reduces compaction, allowing for efficient water movement and preventing hydrostatic pressure buildup.
• #8 Limestone – A smaller-sized aggregate often used as a bedding layer for pavers and slabs, providing excellent leveling properties and enhanced interlock to keep installations secure. Like 6A, #8 is washed clean, and suitable for permeable applications

The Science Behind the Perfect Base

Every professional in the hardscape industry knows that a patio or retaining wall is only as good as its foundation. Compaction is key—without proper density in the base layer, settling, heaving, and shifting will occur over time, leading to costly repairs and dissatisfied clients.

When compacted correctly, 21AA limestone forms a dense, load-bearing surface capable of withstanding repeated freeze-thaw cycles and heavy use. For applications requiring superior drainage, 6A limestone prevents water from becoming trapped behind walls or under slabs, reducing the risk of erosion or frost heave. Using the right combination of materials not only extends the life of an installation but also improves overall performance, making projects more resilient to the elements.

Limestone in the Bigger Picture

Limestone isn’t just vital to hardscaping—it plays a role in nearly every aspect of construction and infrastructure. It’s a key ingredient in concrete, asphalt, and even soil stabilization. Some forms of crushed limestone are used in agricultural applications to balance soil pH, while others serve as filtration media in water treatment plants. The same stone that forms the base of your patios and walkways is also helping to build highways, airports, and bridges across the country.

As we kick off another season, let’s start from the ground up—literally!
Investing time in selecting the right base material and ensuring proper installation techniques will pay off in the long run. If you have questions about which limestone aggregate is best for your next project, stop by and let’s talk stone.

Here’s to a successful season, built on a solid foundation!

Every time I call a market “mature” someone surprises me with a new product. Recently, I mentioned to a friend that Oreos have done just about everything you can do with such a simple cookie sandwich. Change a couple of flavors, add some food dye…what else is there? Then, what appears this summer? Pop Rocks Oreos! Okay, they got me, never saw that coming.

Another surprise to hit the market this year is Alliance Outdoor Lighting’s latest innovation, BT Ally Bluetooth Lamps! Designed with installation contractors in mind, these cutting-edge lamps are set to revolutionize the way you approach outdoor lighting projects. BT Ally have all the tech built right in to the lamp, there is no longer a need for installing entirely new fixtures to enjoy wireless, color-changing functionality.

Let’s dive into the details of the four new types of BT Ally lamps, their impressive features, and how they can seamlessly upgrade older fixtures.

1. BT Ally for Bullets (Spotlights): Perfect for highlighting architectural features and garden elements, these spotlights offer precise control of your light, allowing you to focus attention at areas of interest. With Bluetooth connectivity, you can easily adjust settings from your smartphone, ensuring the perfect ambiance for any occasion.
2. BT Ally for Path Lights: Illuminate walkways and garden paths with style, keeping the light directed downward and out of your guests eyes. The Bluetooth functionality allows for effortless color changes and dimming, providing both safety and aesthetic appeal.
3. BT Ally for Flood Lights: Ideal for larger areas, these flood lights deliver powerful illumination with the added benefit of Bluetooth control. Whether you’re lighting up a driveway or a backyard, you can customize the lighting to suit your needs.
4. BT Ally A19 Lamps: These versatile lamps can be installed into existing porch lights and other traditional fixtures. The A19 lamps are a game-changer for retrofitting older 120v setups with modern, smart lighting solutions.

Features That Shine

• Color Changing: The BT Ally lamps offer a full spectrum of colors, allowing you to create dynamic lighting scenes. Whether it’s a warm white for a cozy evening or vibrant colors for a festive gathering, the possibilities are endless.

There’s a reason I work in the Hardscape Center amidst the limestone aggregate and the concrete pavers... I’m easily distracted by rocks.  (...as you might remember from my previous Sticks & Stones article) It makes perfect sense that my vacation time allows me to get closer to some monumental formations.

On a recent trip to Arizona I was able to check two places off of my bucket list.

The first story begins 50,000 years ago when a meteor slammed down onto what is now Arizona. The impact struck with more power than early nuclear bombs, creating a crater ¾ mile wide, 600’ deep! The shockwave vaporized everything near ground zero, pushing winds outward at over 600mph within a 2 mile radius. Animals over 1 mile away likely were killed by the pressure wave and debris, vegetation was destroyed over 200 miles away, and regional weather would have been affected for several weeks.  

Early non-indigenous people thought the crater was an extinct volcano caldera. In 1902 self-taught geologist Daniel Barringer proposed the idea that the geological feature was actually a collision crater. It wasn’t until the 1950’s that this idea was accepted by the scientific community.   The site of the crater is currently preserved by the Barringer family. It’s a family-friendly tourist site if you’re in the Flagstaff/Sedona area.

This second story starts back even further in time. Just a short drive away from Barringer Crater, but 200 million years back in time, Arizona was covered in forests and swampy rivers.   I was originally excited about seeing so much petrified wood and quartz, but upon arriving at Petrified Forest National Park, I became enamored by the gorgeous colors painted across the mounds of layered sediment. Scattered almost everywhere in the park are logs and pieces of petrified wood. In places, they look like hundreds of petrified wood “headstones”, memorializing a place in time where these trees once stood.

It was a surreal experience walking behind my long evening shadow, feeling the cool sinking air on my face as I strolled between mounds of bold reds and crumbly gray rocks and fossils. Then, to turn around and witness the sun sinking beneath the horizon. To say it took my breath away is an understatement.  I became lost in wonder and pure beauty.     

Historic Route 66 runs through the park, so if you’re thinking of a road trip, this would be an excellent stop.

Where’s next on my bucket list?  Someday I’d like to check out 'Jurassic Coast' in England and The Gates Of Hell in Turkmenistan!

Spring is upon us and we are selling through our mulch at a mind-boggling pace. Hardwood mulch is incredibly popular with homeowners and contractors alike, but have you considered that there is an alternative? What if I told you that this aesthetically pleasing alternative not only suppresses weeds and smells good, it even inhibits several common pests?

Cedar mulch is all of these things!

Mulch, in general, helps the soil retain moisture by preventing rapid evaporation. It acts as a protective layer, keeping the soil temperature stable, and providing insulation for plant roots.

The reddish-brown color of cedar mulch adds visual appeal to garden beds, walkways, and around trees. It complements shrubs and ornamental plants beautifully and can create inspiring contrast to accents on a home or commercial building.

Property owners and maintenance crews may find the battle with persistent weeds is much easier to win with cedar mulch, homeowners may enjoy a landscape that is easier to manage and maintain.

These compounds have been tested for efficacy against gnats and are even available extracted as a pesticidal spray for indoor plants.

Bzzzzzzwhzzzzz….SWAT!!

Another ’skeeter gets smacked, leaving your blood and her guts on your sleeve.

We all love to hate them. They’ve ruined countless outdoor summer gatherings, left me with sleepless nights whilst camping, and can make working outside a nightmare. Do these flying parasites actually do any good for this world?  Should we wish for a perfect eradication method so we never have to hear that buzzing sound again?

Mosquitoes are pollinators. Flower nectar is actually their main source of food. Many of our garden vegetables enjoy being pollinated by mosquitoes, as well as wetland and prairie plants. Are you a fan of chocolate? If so, perhaps you will look at mosquitoes a little differently, as they are the main pollinator of cacao trees!

The females only need a small amount of blood to develop the proteins casings for their eggs. The rest of their time they spend flying around your garden and surrounding areas looking for flowers.

Mosquitoes are a food source for bats, dragonflies, and several birds, such as hummingbirds

The impact of mosquito larva in aquatic environments is difficult to measure, but is significant. They spend their time eating away at detritus matter, cleaning up ponds of decaying leaves, expelling their waste for beneficial microbes to consume.  Mosquito larva biomass makes up a large portion of some fish’s diet. Backyard pond fish and all smaller wild fish eat mosquito larva, providing a strong base in the food chain that feeds larger game fish for sportsmen.

If you want to have fewer mosquitoes in your yard keep your grass well-cut and thick bushes away from your entertaining areas. (This helps with ticks, as well)  Look for places where water may collect and remain still for a period of time so they cannot breed in the puddles. Eliminate empty pots and flip wheelbarrows upside down so they cannot collect water. Childrens toys,  buckets, garbage can lids, even plastic bags that have blown into the yard may collect water.   Fix lawn drainage problems for your customers.  It only takes five days for a mosquito to develop from an egg to a biting adult, so consider any standing water a breeding ground.

We’re off and running into the season here at Christensen’s.  It’s always fun as we see customers again, talking about what we all did over the winter. Some plowed snow or remodeled houses. Some fled south to soak up the warm sun’s rays, whilst others embraced the cold and hit the slopes. The conversation generally ends up on the topic of “what’s new?”

Last year we freshened up the inside of our Hardscape building. This year we are spending time reorganizing the brickyard. You’ll notice several products have been moved to different places. Once you get the hang of it, we think you’ll find it efficiently organized and will be happy with the natural flow of traffic.

We have welcomed Techo-Bloc into our family of hardscape manufacturers and are pleased by the response so far. Currently stocking some of the most popular Techo-Bloc product lines like Blu, Brandon, and Raffinato, we want to hear from you. What Techo products do you like using? –let the guys in the Hardscape building know!

Some new items from Unilock include Treo Smooth. I think of it like a Beacon Hill for sidewalks since the pieces are sized so that you can lay a nice 36” wide pattern. If you want more lines in a patio, but still have an easy time having chair and table legs finding support, Treo is the paver for you!

The Beacon Hill lineup has added more color options in the small recs and a vehicle-friendly 8cm thick version.

Stop in for some strong coffee and let’s talk about What’s New!

While most people in our industry are very active throughout the busy season, as November dwindles into December, many of you will head toward hibernation and less movement. Personally, as my roles have changed here at Christensen's, I’ve found myself at a desk for more and more of my work day.

Of course, we know that there are an astounding number of health and productivity benefits associated with exercise and physical activity. Aside from obvious cardio and flexibility benefits, physical activity can improve concentration, lower stress, and help cut down on snacking at your desk. It really can make the day easier to get through!

When I was working outside I never really thought about how many steps I took, or if I got my heart rate up a couple of times per day, it just happened. Now,I have realized that staying active and flexible needs to be a built-in part of my day.

Here are a couple of ways to fit exercise into your busy schedule:

Stretching is something that I wish I had been doing my whole life. Now, I start the day with a morning stretch as I roll out of bed. It’s a mashup of yoga and a high school gym class warmup. I look like an idiot, but it sure feels great afterward. It only takes a couple minutes!

If the mood hits me right, I’ll immediately follow the stretching with some basic Qigong exercises. Qigong can easily be fit in during a workday. Internet search “qi clearing” for tips on thymus thumping, leg slapping, bouncing. Think about moments when you have a spare couple minutes like when waiting on the microwave at breaktime, or when you get back to your desk before you sit down. I like doing one of my favorites called “knocking on the doors of life” whilst talking on the phone.

Something that I found important to do in the afternoon is getting my heart rate up. That last hour of the day can be tough to get through, but it’s a lot easier when you are feeling invigorated with your blood pumping. Jogging in place is one way, doing some push-ups against a desk works, too. Each day at 3:30 our computers tabulate the days business activity. This “countdown” event has turned into a great a reminder to get up and move! In the Hardscape building, we have endearingly called this afternoon cardio session “Countdown Calisthenics”. Our method encompasses a Nordic walk with a straight leg stretch and a torso twist. Stop by the Hardscape center sometime and mention the "cardio walk." I’ll show you how to do it, and we can share a healthy laugh. 

As I write this article, I am looking at a 4x8 Unilock Hollandstone Premier paver on my desk. It is uniform in shape, density, and color to the rest of the pavers on the pallet it came from. The beginning of this concrete paver’s story is actually set 7000 years ago on a warm Mediterranean island. The Minoans were Europe’s first advanced civilization. Their island of Crete was a hub for trade and artisans. They built fire kilned brick structures, had methods to pump water, and created the first segmental pavement to engineer their way over loose subsoils. The Romans were next, installing 50,000 miles of paved roads. Amazingly, some of these roads are still in use today!

Christensen’s has been around in one form or another for over 90 years. Focusing on the green industry, we’ve been growers, retailers, and now a complete wholesale landscape supplier. Last year you probably noticed our Plant Center was remodeled, this year is the Hardscape Center’s turn! The hardscape yard was added 11 years ago and is an ever-growing part of our company. During the off-season, we considered our floorplan, moved things around, and brought in some new displays. If you haven’t visited us yet, an entirely new layout will greet you as you walk in the door.

It drives me nuts when the grocery store rearranges, and I can’t find the things I need when shopping. However, we spent a lot of time deciding on the intuitive placement of products to help you shop as conveniently as possible. We feel that the new open layout flows naturally and will make your experience in our store more pleasant and efficient.

Our new lighting section includes counter space for fixture demo and a large area for putting together your order.

With the addition of BrickStik Polyurethane Adhesive, we have your vertically stacked endeavors covered. Joining SRW Solvent-Based Adhesive, SRW Rapid-Set Polyurethane Adhesive, and Structure Bond Construction Foam Adhesive, BrickStik is one more sticky solution for your installation tool kit… You can find them all together in our adhesive section.

Perhaps the most striking makeover is to our counter. It has moved to an entirely different area of the store, where our Hardscape staff will be ready to help you with your project. Behind the counter we are displaying our selection of Boar Hog and SRW concrete saw blades, as well as the wildly popular Grabo hand-held vacuum lifter.

Inside isn’t the only place we’ve updated. Outside you will find the fabrics and grids have moved from behind the bulk bins to in front of the Hardscape Center. Speaking of bulk bins… we are thrilled to announce the return of brown hardwood fines!

All the things that you’ve come to expect from the Hardscape Center are still here. And there are even more supplies to make your stop quick and easy. We love the changes… stop by and tell us what you think!

When I was growing up my father and I planted gladiolus corms in our flower garden next to the house. I remember their bold colors reliably displaying each summer. When I moved into my own home years later I found all sorts of new and exciting colors available. They were beautiful that first year, but the following year I noticed that most of my glads didn’t come back. After some internet-sleuthing I realized that they are supposed to be lifted and stored inside for the winter. So why did they always come back when I was a kid?

Microclimate perhaps? Our main flower garden was against a south-facing brick wall, with years of compost mixed into our sandy soil. Glads don’t like a wet bum, so our native, well-drained soil was a good match. The sun-exposed brick wall warmed up the soil, tempering the chilly winter ground.

Could it have been the heirloom varieties we grew? I’m generally a believer that local heritage varieties are hardier. This seems to be the case with gladiolus. In my experience the new fancy ones, though beautiful, are hit-or-miss with successfully overwintering in our area.

Here are some tips to help you on your way to beautiful spires of color each year:

Plant in pots

Be sure your pots are large and heavy enough so the flowers won’t blow over, also make sure they have drainage holes. Add rocks to the bottom of the pot, top with a sandy soil mix. For an extended blooming season plant pots a couple weeks apart, or mix varieties in the same pot. You can add supports to help the spires stand up as they grow tall. There are shorter, and even dwarf varieties available that may work well in pots without support or the fear of wind damage on balconies. After the flowers are spent it could be a good time to move the pots somewhere less conspicuous, as the plant does not rebloom. Sometime before the first frost, dump out the pots and collect the corms, set them somewhere where they can dry in the open air for a couple days, then lightly cover them up to dry further. For final long-term winter storage place them loosely in layers in a cardboard box, separating layers with newspaper. Keep them in a cool dark place where they may nap until spring, protected from animals and sub-40f temperatures.

Leave ‘em in the ground

With a little bit of luck and some forethought you can have success simply leaving your glads in the ground! Moisture and extreme cold temperatures are what you’re trying to manage. To this end, I have found that digging trenches in sunny areas that are not prone to spring puddling works out well. Planting next to a sun-exposed wall is even better! Dig the trench about 14” deep and fill the bottom 3” with rocks. Mix some native soil with whatever amendments are needed to build a sand-heavy blend with a modest amount of organic matter. Plant the corms at various depths as you fill the trench with soil. I’ve sunk ‘em down 8” with no problems. Hardier varieties such as ‘Violet Queen’ and ‘Atom’, as well as many old heritage classics may help you gain an edge on the colder weather.

Glads will do well with a mulch covering the soil and a balanced fertilizer after emergence.