Posts by Steve Arnold
Hardiness Zones, Heat Zones and Microclimates Create More Options
Although you wouldn’t know it from the brutal cold this winter, Greater Nashville is officially in a warmer hardiness zone than it was four years ago.
In January 2012 the USDA updated its plant hardiness map, the first such update in 12 years. Nashville itself had been in Zone 6B; now it is in Zone 7A. The shift, though slight, increased our average annual extreme minimum temperature from -5 to 0 degrees to 0 to 5 degrees (F).
For gardeners, however, those five little degrees make a big psychological difference because Zone 7 is the outside limit for semi-tropical perennials. Perfect World Landscaping is not advising you to rush out and pepper your landscape with plants rated for Zones 8 through 10. That said, the warming trend is good news if you want to add more tropicals to container gardens.
Burgundy Cordyline, with its striking spiked foliage, is a popular option, as are the newer black and gold cannas. A staple of California’s Bay
Area landscaping – Agapanthus africanus, with balls of blue or white flowers on tall stems – also may work in protected containers.
Experiment with microclimates
Microclimates give gardeners more options and a better shot at success when experimenting with tropical plants. A south-facing brick wall, for example, absorbs heat in the day and radiates it back into the environment at night, creating warmer air near it. Fences and large rocks or boulders produce a similar effect.
Filled with buildings and paved surfaces, urban areas usually will have less extreme low temperatures than rural areas only a few miles down the road. A protected courtyard in Belle Meade will not get as cold as a backyard in rural areas of Antioch or Pegram.
Wind protection is another factor, so understanding the direction of your prevailing winds and how they wrap around your home can make for wiser plant choices.
Remember, too, that warmer microclimates in the winter will also be warmer in the summer, which means plants need frequent watering and may scorch if they can’t stand the extra heat.
Not all microclimates are warmer. Because cold air falls and settles, dips and valleys will be colder (and often wetter). Wind affects the tops of hills more intensely, which can create conditions that are both drier and colder.
AHS Heat Zone is another measure
The American Horticulture Society “Heat Zone” map focuses on the other extreme. The 12-zone map uses 86F or higher as the demarcation for temperatures that damage common plants. The higher the zone number, the more days at 86F or above, so Zone 1 is one day or less and Zone 12 is 210 or more days each year that reach 86F or higher.
Most of Greater Nashville is in Heat Zone 7, meaning 60 to 90 days a year at 86F or above.
Remember, both the USDA and AHS maps are guides. What plants thrive where has much to do with topography, nearby structures, expanses of concrete or adjacent large bodies of water. Perfect World Landscaping would be delighted to guide you in choosing the right trees, shrubs, perennials and groundcovers. We can talk about plants all day.
Happy New Year. Now get your gloves out.
A healthy expanse of turf grass is your best protection against the encroachment of winter weeds. But creep they will, because many grasses don’t actively grow in our Nashville winters, and left untended winter weeds will set seeds and create more of a problem the following year.
“Winter annual broadleaf weeds” is the official name for those bright green patches in an otherwise off-season lawn. Edges along planting beds, walkways, pavers and other landscape elements are particularly vulnerable because even a slight space between them and the grass in your landscape is an open invitation.
These are annual pests because the weeds complete their life cycle in 12 months. These weeds are not shy about reproduction; they produce seeds like crazy and those seeds will simply hang out in the soil under late summer, when they’ll germinate.
Winter weeds grow in the winter and flower in the spring, and controlling them while they grow but before they flower is the most effective non-herbicide approach.
Winter weeds to watch
By control we mean ripping them out with as much of the root as possible. But control starts with identification. With the help of the Turfgrass Science Department at the University of Tennessee Institute of Agriculture, we’ve put together some of the most common winter annual broadleaf weeds in Middle Tennessee.
Common chickweed (left) (Stellaria media)
Shiny leaves, vertical hairs along stem. Shallow roots, found in wet, shady areas
Henbit (right)(Lamium amplexicaule)
Square stem, often purplish, with hairy, kidney-shaped leaves. Purple flowers arranged in whorls, or concentric circles. Among winter weeds, Henbit is amazingly prolific.
Purple deadnettle (left) (Lamium purpureum)
Similar to Henbit, but leaves are attached to stem with petioles, or small stalks.
Shepherd’s purse (righ)(Capsella bursa-pastoris)
Deeply lobed leaves in rosette formation, produces a heart-shaped, triangular “fruit” in the spring. Often confused with common dandelion.
Corn Speedwell (Veronica arvensis)
Low-growing, with rounded, toothed lower leaves and smaller, pointed upper leaves.
And special thanks to the UT Institute of Agriculture for allowing us to use their images.
Strong grass weakens winter weeds
The weaker and less dense the turfgrass, the stronger the conditions for these winter weeds to take hold. Overseeding with cool-season grasses creates diversity, density and more protection against invasion.
We’ve identified five common winter broadleaf weeds in Tennessee; but weeds, alas, are not limited to winter or to broadleaf types. UT’s Institute of Agriculture, which has a turfgrass department that works with people and companies in our industry, put together an interactive weed identification chart with photos and details of 42 grassy weeds and 65 broadleaf weeds. Each entry has multiple images that shows weeds in various growth stages, making identification easier before and after flowering.
If your lawn is looking greener than it should in January, you also can give us a call. The weeds aren’t the only ones who work in the winter.
Hardscaping is one of most misunderstood aspects of landscape design.
The word itself may have something to do with it – “hardscaping” sounds, well, hard, or at least solid. But thoughtful hardscaping can soften a rectangular landscape with curves and whimsy. It can create motion, or even a sense of motion, with water features, curved paths or the careful placement of a series of related items.
Hardscaping covers items in the garden that are not living plants, shrubs or trees. Paving and paths of any kind; walls or partial walls of stone, brick or wood (alone or in combination); structures such as arbors, pergolas, gazebos and lattices; decks, benches and a table with two chairs; pots, planters, stones and sculpture – all are hardscape elements.
Hardscaping goals as varied as landscapes
Goals for hardscaping are as varied as the potential elements themselves. The right pieces make a small space feel more expansive or an expansive yard more intimate. Creating focal points, privacy, distinct garden spaces and outdoor living areas are increasing popular goals for our Nashville area clients.
When Perfect World Landscapes has a blank canvas, we work with our homeowners to determine their goals and how hardscaping helps meet them. That might mean a shaded nook under a tree, rimmed by perennials, with an inviting small table and two chairs for morning coffee and tea. It might mean giving a softer form to a large, deep backyard with curved plant beds and curving paths and a midway focal point – a sculpture, a fountain, a raised bed with unusual plant combinations – that invites more wandering.
Arbors can be simple or elaborate, welcoming visitors to the garden or separating two different garden spaces. Even a single decorative ceramic pot will elevate a full perennial bed to different, and more interactive, work of nature’s art.
And don’t underestimate the impact of a few well-placed rocks, especially among low-growing plants such as sedums and other succulents or semi-succulents.
Experiment with easy hardscaping features
Try some small experiments on your own. Grab an old section of worn picket fence and install it near a swath of black-eyed susans and coneflowers. In Nashville, taller sedums such as Autumn Joy grow like crazy; give them a little pop by inserting a birdbath or even just the base of one. Find an urn-shaped pot and balance it against tall perennials, nestled with shorter species set at the edge of a planting bed.
Test and let things sit awhile. You’ll get a sense of what style you like and whether you favor a repurposed cottage-style approach or something more formal, with similar elements that repeat through the landscape.
Not all hardscaping is hard. But some of it is hard work. Designing and building retaining walls, decks, outdoors living areas and pergolas is one of our strengths at Perfect World Landscapes, along with creating the perfect pathways to pull your landscape together.
But if you play a little bit yourself, you’ll know not only what you like to look at but also what you like to use. A quiet, shaded seating area where no one sits may be missing something. A winding path with no focal points makes it far too easy to rush by, without stopping to smell, or at least appreciate, the flowers.
Having a five star lawn in Nashville requires dedication. Our soils are not always in the greatest condition and are frequently not much more than heavy clay and rock. Our climate can be finicky too. We’re in a “transition zone” where we don’t have perfect conditions for one type of turfgrass all year. Our summers are too hot and dry for cool season grasses like Fescue to thrive unless you have an irrigation system and our winters cause warm season grasses to go dormant.
I personally love the winter look of a dormant Zoysia or Bermuda lawn as long as it’s weed free, but most folks want a green lawn all year long. Because of our challenging conditions, the best strategy for growing cool season grass in Middle Tennessee is to renovate the lawn through core aeration and overseeding in the fall each year. The overseeding process will ensure a high quality Fescue lawn.
Overseeding grass is when you apply grass seed to an already established lawn. Before beginning overseeding have your lawn core aerated. Core aeration is one of the best things you can do for your lawn and is ideal for preparing the lawn for overseeding. It mechanically removes small plugs of thatch and soil from the lawn to improve natural soil aeration and increases the penetration of air, water, and nutrients into the root zone of your lawn Core aeration also relieves soil compaction and stimulates new growth. You can rent an aerator and do it yourself, but they are heavy machines that can be tough to handle.
If you have an invisible fence for the family dog, it should be located and marked to avoid damaging it with the aerator. The aerator will find and break the invisible fence wire which is usually buried in the top inch of soil or sometimes just lying on the soil surface hiding in the grass. You may want to call a professional service like Perfect World Landscapes, LLC to handle your lawn renovation. We take special precautions and flag all invisible fencing, irrigation heads, and valve boxes to help avoid damaging them with the aerator.
Fall is the best time of year for core aeration and overseeding. You can get good results in spring but the grass will have a better root system established to help handle the stresses that summer brings if overseeding if done in the fall, .
Always Start With the Soil!
Before beginning the lawn renovation you is is a good idea to have a soil analysis done to determine the soil pH and nutrient levels. The UT Extension Soil, Plant and Pest Center is a great resource for this service as well as many other services for lawn, landscape and garden. (Soil Testing at UT Soil, Plant and Pest Center) If the pH and nutrient levels are not ideal for turfgrass the results will show it. Soil pH is a measure of the acidity or alkalinity of the soil with a scale of 0 to 14.
The neutral point or balance for soil pH would be 7. Soil pH is important because it affects the availability of nutrients to plants and the activity of soil microorganisms. The ideal pH for most grass types is 6.5 to 7.0. If the soil tests indicate too much acidity, then you would need to add lime to increase the alkalinity to reach your target pH. If your soil test indicates too much alkalinity, then you would add sulfur to increase soil acidity to reach your target pH.
Your soil test results will provide you with details on adjusting your soil pH to the level needed for anything you are trying to grow in that location.
Diversify Your Grass When Overseeding
Use a blend of seed with several different varieties for a strong stand of grass when overseeding. The greater the variety of grass seed the lawn has growing the better. Diversity creates a stronger, more disease resistant lawn. Most Fescue seed available is a type of Tall Fescue. You will see popular brands such as Rebels or Southern Gold. Each of those usually has several different varieties of Fescue seed blended together.
Tall Fescue is a bunching grass with broader leaves with a variety of name brands available. There are also Fine Fescues which have smaller, more narrow leaves and include varieties like ‘Chewings’ or ‘Creeping Red’. ‘Creeping Red’ Fescue is a pretty good selection for shady lawn areas, but in my opinion there’s no magic turfgrass that will thrive in shade, at least I’ve not found one yet. Sometimes it is better to create garden beds in shady areas rather than to try to grow a lawn where the conditions are not ideal.
Annual Rye grass is a great choice for a temporary lawn. Annual Rye will grow through the cool season and into the spring then eventually die out when temperatures warm up. Perennial Rye is sometimes used to overseed a dormant warm season lawn to provide green color in the winter. Perennial Rye goes dormant during the warmer months and returns when temperatures cool off. Rye grass grows quickly so you may end up needing to mow your lawn in the winter.
Before purchasing grass seed check the back of the bag for its content. Look for the inert material and weed seed percentages and compare it to other bags of grass seed to find the one with the least amount of inert matter and weed seeds. The label also contains the varieties of seeds the bag so you can adjust your purchase according to what your lawn needs. Measure are of your lawn so you will know how many pounds of seed you need for your situation.
Other Overseeding Considerations
Before you begin your lawn renovation, be sure to mow the lawn a little shorter than usual. Fescue lawns should normally be maintained at 3-4” in height. I like to take a hard rake to my lawn before aerating and seeding to maximize soil contact. Poor soil contact results in lower germination rates.
Your existing grass will also benefit from the starter fertilizer so it will grow quickly while the new seed is waiting to grow. You should try not to mow your lawn after it’s been overseeded until the new grass has germinated and reached 3-4″ in height.
If you are using a grass spreader the most common types to consider are drop spreaders and broadcast spreaders. A drop spreader drops the grass seed directly underneath the bin which allows you to easily control the spread of the seeds on the lawn. Drop spreaders are good for seeding areas around garden beds without accidentally spraying seed into the garden.
Broadcast spreaders cast the grass seed out in a radius around the spreader. These spreaders should have an adjustable guard to prevent casting seed into garden beds. It is very easy to miss areas of your lawn with either spreader so split the grass seed into two batches before you start. When you apply the seed – apply it in two directions to ensure complete coverage of your lawn. Do the same if you’re using a slit-seeder to avoid having tiny rows of grass.
The newly overseeded lawn will need to be kept moist! This may mean lightly misting or watering 2 or three times a day to keep the soil moisture levels ideal for germination and new growth. For an established lawn, an inch of water per week is a good guideline to follow.
Buy a rain gauge or place a cylindrical vessel in various locations around the lawn. Keep the rain gauge away from trees and other obstructions so that it may catch rain or water from the sprinklers to see how long you need to water to attain your goal. A drinking glass or empty can will work just fine. While the accuracy of this method isn’t perfect, it is much better than a guess.
Overseeding your lawn in the fall will provide you with a beautiful lawn that is lush, thick, and very green!
One of the main reasons people enjoy gardening or landscaping is to encourage wildlife to come closer. Homeowners want to be able to commune with the outdoors in a more meaningful way, which can be done by finding ways to improve the landscape for nature’s creatures.
There are many ways wildlife can be nurtured by gardeners. Wildlife needs three things in order to adapt to a landscape: a food source, shelter, and water. All three of these elements can be easily adapted to any garden.
The First Step: Provide Food Sources
Providing food sources should be the first step to of landscaping for wildlife. Food sources can either be provided or grown by planting appropriate plants. Plants that produce seeds or berries provide sustenance for birds, while trees with nuts are great for squirrels and chipmunks.
Hummingbirds love tubular flowers like penstemon and salvia. A simple birdfeeder is a great tool to get a good view of the birds as they fly to your back porch or patio. If you hang a hummingbird feeder somewhere within view will give you a much closer look at the speedy little birds. That said, you must keep in mind that not all birds want to eat seeds or nectar; many enjoy eating insects.
Bluebirds love to fly across open spaces and land on tall poles to find their next meal. Install a pole or two on opposite sides of the open spaces in your yard to give the bluebirds a good place to perch while hunting dinner.
Deer and rabbits love to graze on a variety of plant material. Be careful with encouraging deer, as they will graze on many of the landscape plants that you would like them to stay away from!
Insects are not only an important part of many birds’ diet – they are also an interesting part of nature. Butterflies and dragonflies are fun to watch while bees play an important role in sustaining food sources for other creatures. Bees provide nectar plants to entice butterflies and bees into your garden. Dragonflies are voracious insect predators and love to eat mosquitoes!
A Few Planting Suggestions: echinacea, sunflower, rudbeckia, salvia, penstemon, beautyberry, dogwood, viburnum, switchgrass.
The Second Step: Provide Water
If you have water sources in your garden for birds to bathe in, they will flock to those locations. A birdbath is a very easy way to add a water source to your landscape, but we recommend installing a water feature.
A pond, fountain, or waterfall with a recirculating water pump can create a great space for wildlife while adding the pleasant sounds of nature. Ponds can also allow you to have fish and provide a location for frogs to lay eggs.
The Third Step: Give them Shelter!
Animals are cautious: They are very wary of predators and need to feel comfortable in order to make your garden home. Tall grasses provide shelter for small creatures who nest on the ground, provide cover for birds, and serve as a food source when the grass goes to seed.
Avoid planting bushes too close to feeders as the bushes can also provide cover for predators (like the household cat) which makes it much more dangerous. Keep the feeders several feet away from cover so the birds can have a clear view of the scene.
Bird houses are a great way to attract your favorite feather friends. Select a bird house based on the type of bird you want to invite. Entrance hole size, the size of the box, and its location are very important for birding success! Be sure to hang your birdhouse appropriately for the type of bird since birds differ greatly on the locations they enjoy.
Bat houses are another great thing to add to your landscape. Bats eat hundreds of insects every hour and are an asset when trying to control populations of mosquitoes.
A few rocks here and there can provide shelter for toads and frogs which are a tremendous help when dealing with insect and slug issues.
Landscaping for wildlife can be fun, and it’s very helpful to your garden’s ecosystem. We encourage you to implement these ideas for a beautiful, healthy garden!
There’s no question about it: Everyone wants a great looking landscape. While there are many factors that can help to create the perfect landscape, selecting the correct plants is critical. Living plantings create the character of the garden and can determine its purpose, how much maintenance is necessary, as well as its ecological value.
Choosing native plants is a very good way to create a lower maintenance garden with high ecological value. Native plants are better adapted than nonnatives to our area. When correctly sited, natives can handle the temperature fluctuations, a range of soil types, and drought issues much better than exotic plants.
Echinacea purpurea is the common purple coneflower you see in most gardens, but it has been hybridized with the other members of the genus (E. angustifolia, E. pallida, and E. tennesseensis) to create many colors, sizes, and forms of coneflowers.
Echinacea forms beautiful flowers that not only feed local pollinators but can also feed the birds if it is allowed to form seed in the fall. It likes full-sun locations and can adapt to dry conditions very well.
E. tennesseensis is a native Tennessee coneflower that grows in the cedar glades near Nashville and is well adapted to poor organic soils with high amounts of clay.
Dead head echinacea for the first couple months of flowering to encourage repeat blooms then let it go as fall approaches to create a natural food source for the birds. Echinacea will self sow and is excellent in wildflower gardens, butterfly gardens, or in mixed perennials gardens.
Panicum or switchgrass is a native grass that is very useful as an ornamental landscape plant. There has been some talk about it also being good for biofuels but most people won’t be planting it for that!
There are many unique varieties of switchgrasses that grow well in Tennessee:
- Shenandoah has green foliage that adds red coloration to the leaves as the season progresses.
- Northwind is a tall upright variety with deep green foliage.
- Cloud Nine will grow as high as 67 feet in the right conditions.
Switchgrass is a beneficial food source for birds who enjoy the seeds that are produced in fall.
In the landscape, switchgrass can be used as a screen, a mixed planting with perennials, or even as a potted specimen.
Heucheras are great choices for gardens and landscapes with shady areas. Heucheras (coral bells) are very drought tolerant
plants grown for a variety of interesting leaf features. Their leaf colors can add an impact to a shady sidewalk garden or those hard to plant locations under the trees where there is dry shade.
The foliage can be purple, green, amber, brown, red, or a combination of several different colors. Heuchera need to be divided every few years to maintain their vigor.
This American native perennial is very rabbit resistant and tends to be deer tolerant too although the grazing deer may take a sample first before moving on to more tasty treats. It makes a good substitute for hostas which are enthusiastically devoured by deer.
When planting heuchera – be sure to keep the crown of the plant slightly above the soil to prevent damage from excessive moisture.
All three of these selections are native plants that grow very well in Middle Tennessee. They are tough plants once they are established that survive and thrive when neglected and make for very low maintenance gardens!