Do you have an area in your landscape where you would like to add color and texture? Perhaps a simple plant combo can be a low maintenance solution for you.
Do you want to keep the area somewhat open and don’t want to add trees or shrubs? You don’t want to replant annuals every year either do you? I bet you also don’t want the maintenance of a full perennial garden. Oh, but of course you DO want multi season interest.
Today, lets take a look at some very simple plant combos. These combinations, unlike some perennials that only offer a short bloom time, can be used to add texture and color through several seasons.
Since they are very simple, maintenance is as well as there are not a lot of different plants with different needs. In fact, after they are established, you pretty much just cut them down in late winter before new growth starts.
Grasses provide structure
These combinations work so well because they have an ornamental grass as a major component. Gardeners have been aware of the beauty of grasses for several decades. Grasses can provide texture, color, and structure throughout most of the year. Unfortunately, lots of ornamental grasses used in the landscaping industry can be invasive or at least annoyingly weedy (see Miscanthus).
The grasses we will be using are two of the best for landscape use. Not only are they native to the majority of the US, they also have good fall and even winter fall color. They are the Prairie Dropseed (Sporobolus heterolepis) and Little Bluestem (Schizachyrium scoparium).
Sure there are other great grasses for gardens including native grasses like the strong growing Switchgrass (Read More) or even non invasive non-natives such as Karl Forester Feather Reed (Read More). But today, we will stick with natives that add not only beauty but also ecological value including building the soil and providing wildlife value.
When these attractive grasses are complemented with a long flowering perennial with an interesting form, you have a simple planting combination that can be applied over a fairly large area and look attractive for most of the year.
Three Simple Plant Combos for Sun
These plant combinations include an ornamental grass and the plants should be spaced 18 inches apart from each other in Full Sun conditions.
Simple Plant Combo #1, Prairie Dropseed and Summer Beauty Ornamental Onion
This is a planting that will provide a long bloom time of the Onion with the nice textural effect and later fall color of the grasses. One nice thing about this combo is that after they are established, they will requires little to no supplemental watering and no fertilizing. You want to place these plants 18″ apart from each other.
Prairie Dropseed (Sporobolus heterolepis), 60% of the plants
This native grass forms an arching mound of foliage 15″ tall and 18″ wide which gradually widens. The leaves turn a golden bronze with orange hues in fall, which fade in the winter. The flower panicles appear on slender stems which rise over the foliage in late summer to 2 to 3 feet tall.
Summer Beauty Ornamental Onion (Allium ‘Summer Beauty’), 40% of the plants
This long blooming beauty was discovered and introduced by Roy Diblik. It spreads at a moderate rate over the years, but its sterile flowers don’t become invasive. It’s foliage emerges in Spring and provides some green to the planting area before the slower emerging warm season Prairie Dropseed.
It grows 12-18” high and 18-24” wide.
Combo #2, Prairie Dropseed and Pale Purple Coneflower
Pale Purple Coneflower (Echinacea pallida) 40%
Instead of Summer Beauty onion, we will substitute later Summer blooming native, the Pale Purple cone flower (Echinacea pallida). This will help to provide peak interest from Summer to Fall.
While similar to the Purple Coneflower both in range and appearance, it grows shorter. It is also beloved by pollinators and gives a bit more of a prairie vibe. You want to space the plants 18″ apart in this combo also, although you could space the Pale Purple Coneflowers as close as 12″ from each other to fill in quicker .
The Pale Purple Coneflower grows 2-3’ tall by 12-18” wide.
Another lower growing species coneflower that could be used is the Yellow coneflower (Echinacea paradoxa).
Simple Plant Combo #3, Little Bluestem and Purple Coneflower
This great combo grows a bit taller then the last two. The plants in this combo should also be spaced about 18 inches apart.
Little Bluestem (Schizachyrium scoparium) 40%
Little Bluestem is a native, warm-season grass with bluish gray-green foliage and an attractive reddish bronze color in autumn. It likes Full sun but can take a little bit of shade and tolerates a wide range of soils.
A great thing about this grass, is there is no reason if you are patient enough to let it develop over a few years, why you can’t start a planting with direct seeding. This can allow you to plant a large area for much a smaller cost then buying containerized plants.
Little Bluestem will tend to flop a bit in the winter more then some other grasses (like Prairie Dropseed), but it is still attractive due to it’s color effect. It readily reseeds so it is not recommended for small gardens where it does not have room to move a bit. This is also a reason why we plant 40% of these combos Little Bluestem when we planted 60% of the Prairie Dropseed.
In winter the seeds are of particular value to small birds. Other wildlife uses of Little Bluestem include providing cover, nesting material.
Little Bluestem grows 2 to 4 feet tall and 1.5 to 2 feet wide.
There are a few selections available. ‘Blaze’ has great winter color. It was originally selected by agronomists for use as a forage grass It has vivid red fall foliage turns pink in the winter. It is very adaptable, growing easily even on clay soils. It will grow to 3 feet high and 15″ wide in most climates.
‘The Blues’ is a commonly available cultivar. It has deeper blue foliage that turns purple to burgundy in the fall. It will grow 30″-3′ tall and spread to 18″. Use it instead of the species in your simple plant combo if you want a bit more blue color to your landscape.
‘Standing Ovation’ is a more upright growing form and may be a good choice if you are growing little bluestem in rich soil (in which they tend to flop more). They should hold up better in the winter too.
Purple Coneflower (Echinacea purpurea) 60%
As Little Bluestem is a taller grass than Prairie dropseed, we need a taller flowering perennial plant. Now is the perfect time for the good old standby Purple Coneflower. It’s greater height allows it to reach above the Bluestem foliage. For more info on Purple Coneflower see my post on plants I hated to leave behind at my old house.
Echinacea purpurea grows 3′ to 5′ tall and spreads to 1.5 to 2 feet wide.
HOW MANY PLANTS WILL YOU NEED FOR YOUR SIMPLE PLANT COMBO?
To figure out how many of each plant you will need in your simple plant combo is a simple calculation.
Since the spacing for all the combos is 18”, you need one plant for every 2.25 square feet of space you want them to fill.
Say you have an 12 feet by 8 feet area you want to plant the first combo of Prairie Dropseed and Summer Beauty Allium.
X 8 feet
72 sq ft
The spacing of this combo is 18 inches. So to figure out how many total plants you need you will divide 36 sq ft / 2.25.
72 sq ft/ 2.25 sq ft per plant = 32 total plants.
Note depending upon how you arrange them you might want an additional plant or two.
Since 60% of these will be Praire Dropseed, you know you will have 19 of that grass.
19 Prairie Dropseed
40% will be Summer Beauty Allium.
LAYING OUT YOUR PLANTING
So how should we place these 16 plants in our space?
Your best bet would be to lay them out in offset rows, placing the plants 18 inches from each other. When you first start try to make groups of different size of the two plants, don’t agonize about which plants you put where, just get the layout and spacing right. Don’t put all of one plant in one area, but instead try to mix them up a bit.
When that’s all done, you can step back and start switching the Alliums with the Dropseed until it looks right to you. For you, this could be a very regular pattern or it could be a looser more random looking informal pattern where you have more alliums in one area and less in another. Your individual tastes can dictate just how your simple plant combo is arranged.