Plant these perfect (according to our own Doug Oster) perennials

October 6, 2018
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Butterfly weed is a great perennal pollinator plant that helps monarch butterflies and many other insects.

With rain on the way, I’m digging planting holes for new perennials found on sale at my local nursery. Perennials are plants that return year after year in the garden, and fall is the perfect time to plant them.

Now’s a great time for the plants to get their roots established by watering them until the ground freezes, as rain is scarce, and putting them to bed with a layer of mulch. The mulch is spread around the plant -- never touching the stem -- where it acts as a blanket, stops frost heaving and keeps the soil evenly moist.

Each planting hole gets a generous dose of compost, mixed well with the native soil. It should be twice as big as the root ball and the plant should not be planted any deeper than it was in the pot. Improving the planting hole is essential, as many of these plants will outlive the gardener and giving them a good home will make them thrive for decades.

It’s much less stressful on the plants when they are put in the ground on a cool, rainy day. It feels good to be planting on a day like this, but sometimes the timing just doesn’t work out. When it’s sunny and warm, wait until later in the day to plant. The perennials will have all evening to prepare for the next day.

Why perennials?

The advantage of perennials over annuals is that they don’t need to be replanted each season. The downside is that these plants usually only bloom for several weeks. Annuals will flower for most or all of the frost-free season. I couldn’t live without my impatiens, marigolds and other annuals, but I keep adding more perennials each season.

The fun part is deciding where spring, summer and fall bloomers should go. The first consideration is whether they like sun or shade. It breaks my heart to see a hosta struggling in full sun during a July heat wave, and sun lovers won’t bloom or grow strongly in the shade.

In general terms, tall plants go in the back of the border and smaller in the front.

I’m often asked what I would recommend to grow, and I’ll list some favorites here, but grow what you love. Spend time at a good local nursery asking questions and looking at plants. Remember, for most of the year it’s the foliage that takes center stage, and the flowers are the gravy. If the colors, texture and form move you, that plant should go in the landscape.

Explore the garden centers for some new and interesting plants for your garden. They will keep you happy for years to come.

Doug’s favorite perennials

Longtime readers will be familiar with one of my favorite perennial plants, but since it only has a Latin name, for others this will be the introduction to Corydalis lutea. It starts blooming in April and will continue to flower into November. Corydalis grows in dry shade or part sun and is deer resistant. The plant makes a nice colony in a couple of years by throwing seeds, not invasive underground runners. This low-maintenance plant needs nothing from the gardener and is even the perfect addition to a container due to its long bloom time.

I’ve been experimenting with perennials in pots by using corydalis and different types of ivy. A beautiful, hardy variegated ivy can be found at nurseries for a song this time of the year and makes a great “spiller,” softening the edges of pots.

Butterfly weed, swamp milkweed and common milkweed have become a big part of the gardening world as a way to help monarch butterflies. The species (asclepias) is the only host plant for the insect. All three are easy to grow in part to full shade and are deer resistant, too. Don’t let the word “weed” in the names of these plants throw you. All three are beautiful and are a great choice for any garden.

Perennial hibiscus grows in part to full sun, blooms later in the season and is deer resistant. I’ve never watered or fertilized the cultivars in my garden. Some have huge flowers the size of dinner plates.

Anemone or windflower is another carefree plant with many different cultivars. ‘Queen Charlotte’ has intense, purple buds that open to pretty, light purple flowers that sway in the breeze. The deer will nibble on the buds, but don’t like them.

Ligularia is a shade-loving perennial which, once established, will bloom for decades. I grow ‘Britt Marie Crawford,’ which has purplish, bronze foliage and then spectacular yellowish orange, daisy-like flowers. Even though it has a reputation as a plant that likes moist areas, I’ve never watered this one.

Hostas are deer candy, so keep that in mind when planting them. The foliage can be as small as a mouse ear or three feet across. There are a wide range of colors and variegations too. As long as you can keep the deer off them with something like Bobbex, this is a great plant for the shade.

Daylilies are almost as attractive to the deer as they are to the gardener. They love full sun and come in a plethora of sizes, shapes and colors. Reblooming varieties can flower for more than 200 days. ‘Stella de Oro’ might be the most popular, with its short yellow blooms, but there are many different types out there.

Peonies are a spring favorite, as many have an intoxicating fragrance and are maintenance free. Some suffer from fungal issues later in the season, but nothing serious.

Perennial salvias are one of my all-time favorite plants. They are deer resistant, tough and beautiful. They love full sun, but will take some afternoon shade. ‘May Night’ is a long bloomer that is nearly indestructible.

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