Perennials are plants that live 2 or more seasons and are usually cold hardy. Trees and shrubs are technically also perennial, but we’re focusing on the herbaceous ones like rhubarb, delphinium, and Echinacea. There’s a great diagram on Colin’s PowerPoint presentation (see below in “resources”) showing the life cycle of a perennial. A perennial begins the season growing vegetative growth. It progresses to a flowering state before developing a seed. Heading into autumn, the perennial will prepare for winter by falling into dormancy. The plant will stay in that state until it begins the cycle again next spring.
Types of Perennials
Here’s a little garden inspo for the types of perennials you can grow in Calgary which is zone 3/4. Keep sun exposure in mind. Keep benefits like bees and fragrance in mind too. Perennials don’t all bloom at the same time! When selecting perennials for your garden, consider adding diversity so you can appreciate blooms in spring, summer and even fall.
- Spring Bloomers
- Summer Bloomers
- Fall Bloomers
- Sedum (SUN) (GROUND COVER) | IN STORE
- Heuchera (SHADE) | LINK
- Golden Rod (SHADE)
- Joe Pye Weed
This is by no means a comprehensive list. Feel free to visit your local garden centre and see what’s growing where you live.
Fun Idea: Moon Gardens
Have you heard of these? Colin had the opportunity to sit in one under the full moon and would absolutely recommend trying it. A moon garden consists of white or pale flowers so the moon can easily illuminate them. Add in some lighter foliage too. You don’t have to do your entire garden, just a section that the nocturnal pollinators can find and you can enjoy from your patio or something.
Consider the end goal when deciding on a location for your new perennial. it will eventually grow to the size on the tag, so plan for that. Make sure it’s getting the right sun exposure. Will another plant shade it, therefore depleting it of much needed sunlight? Furthermore, beware of pathways and gates as the plant may crowd them. Also, consider planting by bloom time. Place different bloom times together so you can get a diversity flow of flowers throughout the growing season. See examples above.
How to Plant
Always loosen and amend your soil. This should actually be done every year, but exercise caution for tender roots on more established plants. Perennials do best in a garden bed as opposed to pots and raised beds so you can stick to your more heavier and rich amendments. See below for Colin’s recommendations. You’ll want to amend only 2-4 inches down. Any deeper, you’re wasting your money. Dig your hole bigger than the plant and place the plant in so the root ball is ground level. Back fill and firm down. Water heavily. See watering tips below. You may also want to top with a mulch and get the added benefit of moisture retention and weed control. If your perennial will become big a bushy by the end of the season, also consider installing a cage or stake early on for additional support.
- Sea Soil Compost | LINK
- Mulch | Cedar, Charcoal, Redbrick, Chocolate
- Tomato Cage | LINK
- Peony Ring | LINK
- Plant Stakes | LINK
Transplanting Existing Plants
We had a great question from a participant who was wondering about transplanting ferns. Basically, they had a major deck project done last year and unfortunately her perennial ferns were damaged. Colin recommended that they wait to see if anything comes up in the spring because they may be totally done. Ferns can be resilient, so if there is new life popping up, then dig them out, and plant them in another shady spot. Treat that new transplant like a new plant. Use a transplant fertilizer and water daily for the first couple of weeks to establish roots.
This kind of approach will work for most perennials. If you’re ever unsure though, reach out to out perennial department to learn the best course of action for your specific plant.
- Transplant Fertilizer | LINK
If you need to transplant a bunch of plants, say your renovating an entire bed, then here’s a tip. Dig a trench away from the space you’re fixing. Put perennials in and cover the roots with soil. Water. This will protect and hydrate the roots so you can spend the day renovation the garden. You don’t want those roots exposed to sun and drying out.
Caring for Perennials
Removing finished blooms/stem so the plant doesn’t create a seed pod. This is different than cutting back which is done at the end the end of the growing season to prepare it for winter and clean up the garden bed. Based on the perennial, you can remove either the bloom or the entire stem. There’s a great diagram in Colin’s PowerPoint which you can access below. not only does deadheading redirect energy to producing more flowers, but it can help keep your garden looking tidy.
Here’s a great tip from one our participants today! Consider leaving seed pods on your perennials over the winter so the birds have access to food. Leave the stems to give bees, and other garden friends, some habitat support over winter and early spring.
New plantings will require water everyday for the first couple weeks to help establish roots. Taper off at the plant establishes and Plants in bloom need a lot of water to produce flowers, so consider watering more than usual. Continue watering until dormancy in the fall. In Calgary, we get chinooks, so you may want to water periodically throughout the winter. You don’t need to soak it like the summer, but a little here and there is okay. Water won’t hurt the plant over winter.
- Soaker Hose | Even, gentle watering | LINK
- Nozzle | LINK
- Watering Wand | For reaching into deep gardens | LINK
Start a fertilizer program after planting, or as soon as the garden wakes up in May. Always follow manufacturing directions because they stand by their product. Don’t try to use a more concentrated mix because you could encourage burning your roots.
- Promix Bone Meal | LINK
- Colin’s Fav. Slow release fertilizer you sprinkle on. Great if you have a busy life and don’t want to think about fertilizing every week. Can also be used when planting bulbs, so a great tool to have on hand.
- All Purpose | LINK
- Perfectly fine if you’re looking for a general fertilizer for the whole garden. All three numbers are the same.
- Perennial & Vine | IN STORE
- Specialized fertilizer if you primarily have perennials and want the best of the best.
Next Webinar | Trees – Spring Selection and Care | May 6, 2023