Delaware Gardener in the News Journal: PLANTING GROUNDCOVER IN LANDSCAPE BEDS

Sustainable landscaping depends upon learning from natural systems and trying to recreate the elements that make them successful in the planned and planted landscape.  So, let’s look at a natural woodland or forest.  It usually has a canopy layer comprised of tall trees like tulip poplar, sycamore, oak, hickory and maple.  Then there is an understory tree layer.  This may contain beech, ironwood, dogwood, redbud, and birch, to name a few.  Next, the shrub layer in our woods is comprised almost entirely of spicebush because our rampant population of white tail deer has eaten everything else, but it should contain other native shrubs like viburnum, witch hazel, winterberry holly and deciduous azalea.  That takes us to the ground layer – also primarily eaten by deer in our natural woodland—but important in a functioning forest.  The ground layer reduces erosion, helps water infiltrate and provides competition for invading plants.

So, let’s focus on that ground layer, which is often forgotten in the planned landscape.  People seem to have almost as strong a love affair with mulch as they have with mowed lawn.  The ultimate goal of a planted landscape should not be to have individual shrubs that are surrounded by brown mulch!  That’s not sustainable because mulch must be reapplied every year and it doesn’t look natural.  Instead, the goal should be to have a solid mass of ground covering plants as the ground layer with shrubs and trees coming out of that mass.  This may take a little while to establish and mulch is a good temporary solution to reduce erosion, increase infiltration and reduce weeds.  But, plan to have your plants take over this responsibility ultimately.

When planning your ground cover, think about using large masses of relatively few types of plants.  Too many different plants will appear confusing and detract from your trees and shrubs.  Decide where ground cover is needed.  Some shrubs are low to the ground and do not need ground cover plants below them, but others are higher branched and would look great with a uniform ground cover underneath.

Here are a few good ground cover plants. Allegheny pachysandra is our native pachysandra and while it takes a little while to become established, looks great once it gets going.  There are many great native and non-native ferns the deer don’t eat them.  Yellowroot is another native groundcover that grows well in wet soils but also tolerates dry conditions.  It has somewhat inconspicuous purple spring flowers but turn yellow in the fall. Wood aster is a great ground cover for both shady and sunny locations.  There are many sedges (again some native and some non-native) that can form a nice carpet in the landscape.  Barrenwort is not native but is one of the best ground covers for dry shade.  Plumbago is another non-native that grows well and has blue late-summer flowers and burgundy fall color.

Ceratastigma plumbaginoides (plumbago) as a ground cover at the Delaware Center for Horticulture (photo by Gary Schwetz).

Carex ‘Blue Zinger’ starting to fill in this landscape bed as a ground cover beneath the sweet bay magnolia.

My project over the weekend was to install a new landscape bed at the edge of our back woods that will provide some screening for an outdoor shower.  My daughter, who is a graduate student studying green roofs at the University of Maryland was home for the weekend to give me some “expert” help.  We left a hose out in the sun so it became pliable and then used it to delineate a new bed line.  Liz made the line, while I stood on the deck one story above to look at the overall effect.  Once we were satisfied we marked the line with flags.  Then I edged the bed with a spade.  Next, I got my handy sod lifter (a tool I received from my father that many friend have borrowed over the years).  The sod lifter has a flat blade and a crook in the shaft that allows you to lift sod while remaining relatively upright.  It works like a charm but still takes some elbow grease.  I put the lifted sod in a wheel barrow and dumped it in the compost pile.  Next, I laid out my plants–a sweet bay magnolia, 2 sweet shrubs (Calycanthus floridus), a deciduous holly and lots of ‘Blue Zinger’ Carex–all purchased from the University of Delaware Botanic Garden plant sale.  I was able to divide most of the carex in half or thirds so they covered much of the ground layer.  After planting, I took my lawn mower into the woods edge and mowed up some old leaves. I emptied the clippings bag onto the bed and viola–natural looking mulch (for free!).  The best news was it then proceeded to rain for 2 days–perfect for my new landscape bed.

Yesterday I ran my first half marathon with my daughter for Mother’s Day (actually she ran ahead of me by about 15 minutes but we were together before and after the race!). So, my husband cut at least half the lawn this weekend.  I suggested this is a trend that might continue? Got a chance to plan a new bed that will screen an outdoor shower and house a sweet bay magnolia I got from the UDBG sale.  My older daughter (landscape hort. masters student at U of MD) and I worked with a hose and siting from our deck to get the bed line just right.  There are a lot of white violets mixed in the lawn in what will now be bed, so I hope to lift the “sod” maintaining as much of the violets as possible as a ground cover.

We are lucky to have had a slow, long spring so far to help us complete all those necessary gardening tasks.  This weekend, my husband and I worked on the vegetable garden.  We have a huge garden space and don’t need to plant the whole area every year, so last year we covered a portion of the garden with a large square of black plastic, hoping to reduce our weeding responsibility and it worked! Two weeks ago we moved the square to a different area and uncovered a wonderful, weed-free space for planting tomatoes and peppers this year.  He asked me on Friday night if there was a product that would cover the soil but allow water to penetrate to reduce weeding around the tomotoes and peppers this year.  I said, “Sure, landscape fabric or weed mat will do that.”  So, off to the garden center I went on Saturday morning to purchase the fabric.  We are trying two strategies: 1) leaving a 1′ wide open space for the planted tomatoes and 2) butting the lengths of fabric up to one another with the planted tomato in between.  We’ll see which works better.

Besides the vegetable garden, I cut back beauty berry shrubs and weeded a few landscape beds.  Two weekends ago, the main garden task was mowing meadows and using the “clippings” (which are full of leaves, chopped up stems, and lots of good organic matter) as mulch on landscape beds.   Other completed tasks this spring include: spraying glyphosate on honeysuckle before anything else came up; pruning back raspberries and blackberries; moving peonies into the vegetable garden to avoid deer browse so we can finally enjoy some flowers; cutting back warm season grasses (some with a mower and others with a weed eater); and weeding, weeding, weeding!

Spectacular plants this spring included: corylopisis (winterhazel) with their popcorn yellow hanging racemes, ‘Elizabeth’ magnolias with their pretty yellow blooms, hellebores in different shades of pink, rose and purples greeting us by the front door and a while ago we had a carpet of snow drops, with their nodding white flowers.

*Delaware Gardener in The News Journal:

Sustainable is certainly the buzzword of the decade, but what does it mean when it comes to managing your garden? Sustainable involves letting natural systems occur and providing as few inputs as possible. We’ve already talked about one sustainable practice in Delaware Gardener this year—wait until fall to fertilize your lawn. What else can you do to manage your home landscape sustainably?

First, there is no need to go out and buy tons of new mulch every year. What can you use from your own site that will function as a mulch to keep moisture in and reduce weeds in the garden? Leaves and any other yard waste you’ve composted make great mulch. Chip up leaves that are remaining from last year with a lawn mower and spread them on your landscape beds. The first time you cut the lawn in the spring; there will probably be enough leaves in the mix so you get a nice mulching material to spread on your beds. If you’ve composted your own yard waste over the winter, it will be ready to spread this spring. You can also get composted yard waste from a variety of sources, including the City of Newark site on 896. It is free to anyone with a pick-up truck or vehicle capable of hauling mulch. You also may have enough mulch on your beds and all you need to do is use a hard rake to loosen the crust and spread it evenly over your landscape bed. Ultimately, the goal of any garden should be to have plants cover the ground so you don’t need new mulch every year. Think about the natural system of a forest—leaf litter, ground cover, shrub layer, understory trees and canopy trees make up all the layers you need in a landscape.

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