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Ornamental Grass Pruning – A Winter Task

Ornamental Grass Pruning – A Winter Task

The term “ornamental grass” is a catch-all phrase used to describe grasses and “grass-like” plants.  Individual species are adapted to a wide variety of landscape sites (i.e., wet or dry, sun or shade, hot or cold climates, and varied salt tolerance). Growth habits range from low ground covers to intermediate shrub-like plants to very tall hedge-like plants. Ornamental grasses are very dynamic; the size, shape, texture, and color of grass changes with every season.

Deciduous Ornamental Grass

Grasses with foliage that dies in the winter and remains dormant until the weather warms in the spring are considered deciduous.  The winter character of deciduous ornamental grasses adds tremendous interest to the winter garden when contrasted with evergreen plants or structures such as walls or fences.  The dried foliage of deciduous grasses creates sound as it expands and contracts in response to changes in temperature or moisture, while interaction with wind creates movement in the garden. For these reasons, pruning of the dead foliage and inflorescences is not recommended at the time of the first frost.

Pruning of ornamental grasses should be done in late winter or early spring, just prior to new shoot growth.  In Northwest Florida, gardeners should target the end of February to prune ornamental grasses.  For deciduous grasses, such as Japanese silver grass (Miscanthus sinensis), the old foliage may be completely removed within inches of the soil. Be cautious to not remove the growth point by leaving the grass clump at least 4 inches high.  For evergreen grasses, such as muhly grass (Muhlenbergia capillaris), the ragged leaves can be removed to neaten the appearance of the plant without shortening all the way to the ground. So, depending on the damaged portions, the remaining grass clump can be 6-18 inches high after pruning.  Grasses recover quickly from a heavier pruning.  Within a few months the plant will have completely regrown.  If desired, old flower stalks and seed heads may be removed any time they no longer have a neat appearance.  For more information on ornamental grass species and growing tips, please visit the EDIS Publication: Considerations for Selection and Use of Ornamental Grasses.

Proper Tree Planting

Proper Tree Planting

A newly planted tree with water retention berm.

A planted tree with water retention berm. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County

Often, Extension agents are tasked with evaluation of unhealthy plants in the landscape.  They diagnose all sorts of plant problems including those caused by disease infection, insect infiltration, or improper culture.

When evaluating trees, one problem that often comes to the surface is improper tree installation.  Although poorly installed trees may survive for 10 or 15 years after planting, they rarely thrive and often experience a slow death.

Fall/winter is an excellent time to plant a tree in Florida.  Here are 11 easy steps to follow for proper tree installation:

  1. Look around and up for wire, light poles, and buildings that may interfere with growth;
  2. Dig a shallow planting hole as wide as possible;
  3. Find the point where the top-most root emerges from the trunk;
  4. Slide the tree carefully into the planting hole;
  5. Position the point where the top-most root emerges from the trunk slightly above the landscape soil surface;
  6. Straighten the tree in the hole;
  7. Remove synthetic materials from around trunk and root ball;
  8. Slice a shovel down in to the back fill;
  9. Cover the exposed sides of the root ball with mulch and create water retention berm;
  10. Stake the tree if necessary;
  11. Come back to remove hardware.
A hole being dug for a tree to be planted.

Digging a properly sized hole for planting a tree. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County

Removing synthetic material from the root ball.

Removing synthetic material from the root ball. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County

Straightening a tree and adjusting planting height.

Straightening a tree and adjusting planting height. Photo Credit: Matt Lollar, University of Florida – Santa Rosa County

For more detailed information on planting trees and shrubs visit this UF/IFAS Website – “Steps to Planting a Tree”.

For more information Nuttall Oaks visit this University of Arkansas Website.

Are You Ready For Freezing Nights?

Are You Ready For Freezing Nights?

Frost on Dune Sunflower
Picture by: Pam Brown
UF/IFAS Extension

December is finally here and that means consistent nights of watching for dropping temperatures.  Tropical plants and newly installed shrubs are susceptible to cold injury.  Those colorful, blooming plants that have added a tropical look to the landscape all summer may begin to suffer when the temperatures drop below 500 F.  Leaves may turn yellow and flowering stops. These plants will need to be moved inside or have temporary greenhouse built around them.  But, hardy plants that haven’t established a sufficient root system will also need additional attention when the temperatures drop dramatically.

The ability of plants to endure a freeze depends on the species and the weather leading up to the extra cold night.  Gradual decreases in temperatures helps plants acclimate to winter.  But, a sudden one day drop of 40-50 degrees results in a rapid freeze that causes ice to form inside the plant cells.  Leaf and stem tissue expands so quickly that it splits, resulting in parts of the plant incapable of transporting water and nutrients, as well as, performing photosynthesis.  However, it may be late the following spring before the damage is noticed, when that section of the plant has slowly staved to death.

Cracked bark from frost

Additionally, plants can experience desiccation or drying out.  This happens when dry winds and solar radiation result in the loss of more water from the leaves than can be transported by a cold root system.  The resulting symptom is marginal and/or tip burning of leaves that leads to totally brown leaves.

Freezes (when the temperature drops to 320 F) are characterized as radiational or advective.  Radiational freezes occur on calm, clear nights when heat radiates from the surfaces of plants, making them colder than the air due to the rapid loss of heat.  If there is moisture in the air, ice will also form on the surfaces.  Under these conditions, ice forms between plant cells, rather than within the individual cells.  Most hardy plants can tolerate these type of freezes if they are properly hydrated.

Advective freezes occur when cold northern winds move in rapidly, dropping temperatures quickly, and causing widespread foliage desiccation. Cultivation and maintenance practices can impact a plant’s ability to endure extended periods of low temperatures.  Shade-tolerant species installed under the canopy of a tree typically display less injury from radiational freezes because the trapped heat from the ground and the overhead foliage creates a microclimate.  Well-watered soil around a plant will absorb solar radiation during the day and re-radiate heat over night, raising the temperature around the plants. Shrubs that are not pruned in the late summer or fall have leaves that can withstand frost and wind.  But, the removal of foliage late in the growing season triggers a flush of new growth, that is very sensitive to lower temperatures. The same response can result from fertilizer applications after plant’s have slowed down in growth.

Irrigation Frost Protection on Citrus

Row Cover
Picture by: Univ of Maryland Extension

So, what can you do to prepare for upcoming freezing temperatures?  Begin by avoiding pruning and fertilizing at the end of the season and making sure that the plants have been watered within 24 hours of a cold night.  Next, insulate against water loss and increase heat radiation by adding a three-inch of mulch, as well as, covering the trunks of sensitive trees with a commercial tree wrap.  Then, consider what needs to be covered.  Frost cloth or other breathable fabrics can trap heat for the night and provide a protective layer from frost settling on the leaves.  It needs to be placed by mid-afternoon and removed the next day when temperatures are above 320 F.  Plastic is not recommended unless the timing regime can be followed reliably and a structure is used under the material to keep the plastic off the foliage.  Anchoring of the cover is critically important in the event of an advective freeze.

Finally, turn off the sprinkler system.  Commercial agriculture often uses a running irrigation system to keep the leaf surface temperatures near, but not below, 320 F because sprinkling utilizes latent heat released when water changes from a liquid to a solid state.  The thin layer of ice melts and re-freezes on the surface throughout the night, without ice forming within the plant tissues.  For the technique to work, sprinkling must begin as freezing temperatures are reached and continue until thawing is complete.  Landscape systems are not designed to deliver the amount of water over the length of time required to accomplish this type of frost protection.

When the cold nights have passed, don’t forget to check your plants for water. But, wait until winter has passed before pruning out the frost damaged stems.

Creative Landscape Design Brings Dramatic Change

Creative Landscape Design Brings Dramatic Change

Photo credit: Stephen Greer, University of Florida/IFAS Extension

Landscapes are an ever-changing setting that can be fun to view as the seasons come and go.  We all have differing ideas of what an exceptional landscape should be.  The point to always keep in mind is what you and your family like.  Are you considering the Florida-Friendly Landscaping elements?  You always want to keep a healthy, attractive environmental sound landscape.  This brings many interesting design concepts to the table.

The kitchen table is exactly where a landscape design needs to begin.  My dad was just the opposite, he would receive or buy plants on impulse.  Load up all these three-gallon plants, take them home and plant without consideration the long-term growth, color combinations, time of bloom and many more topics.  He just loved working in the yard and growing plants.

Photo Credit: Stephen Greer, University of Florida/IFAS Extension

There are basic principles of landscape design that are used as a guide. While I may stray from them from time to time, I always return to these principles.  Just keep in mind that a landscape is an ever-changing living setting that we will always work to improve.  The visual elements are based on what you see first when you enter a setting and are usually the vibrant high impact plants that may include bright bloom color, size of plant, focal plantings, leaf size and others.  The other side of the visual is the subtle presence of low impact plants with softer colors, small leaves, lower growing plant size.  This visual group often is planted en mass with a flow of plants to create a calming effect for the visitors to your landscape.

When the form of the plant is being considered, there are several points to keep in mind.  Will it have a three-dimensional impact in the landscape setting?  Is the landscape a small backyard or a one-acre open setting?  What are the maintenance requirements of the plant(s) as they mature in size?  A large tree can dominate a small area, but it may be just what is needed for shade with low plantings around it.   In a large setting, multiple large trees may be needed to create a focal point.  I have seen some wonderful tree alleys that help in directing the flow of the landscape down drives, walks, and paths.  These forms should be considered for all plants in the landscape including, trees, shrubs, groundcovers and even hardscapes.

Photo Credit: Stephen Greer, University of Florida/IFAS Extension

Up next is the texture of the plant(s).  Are you looking for large and coarse or small, “softer” leaves?  You may find finely textured plants along paths or at entry areas to steps, softening the hardscape of the steps.   Are the large leaved plants open and airy, allowing light to flow through?  Large coarse leaved plants may be found at the back of landscape beds with fine textured smaller plants in front creating a three-dimensional look or even used as a focal point to pull the gaze of the eye to a determined location.

Color in the landscape has just as much impact as the plant texture, size and form.  Color can bring a bold or a soft statement.  The color is often thought of from blooms, but leaves too change in color with the seasons, from a fresh new bright green, purple, red or other colors in the spring to deeper, more mature colors as summer comes in.  Trunks can also bring unique colors to the landscape from subtle yellows to cinnamon.

There are so many things to think about when creating a long-term vision for your landscape.  Many options come in the decisions that will need to be made.  Do your research and always contact your local Extension office for more information!

 

 

 

A Landscape Combo for Native Fall Color:  Muhly Grass & Darrow’s Blueberry

A Landscape Combo for Native Fall Color: Muhly Grass & Darrow’s Blueberry

In the Panhandle, fall is the prettiest season for wildflowers.  Our roadsides and woodlands are covered with pinks, whites, yellows, blues, purples, and even a little red here and there.  Pretty as it may be, the beautiful wildflower look isn’t super appropriate for most yards.  It would look unkempt, a little “wild” if you will, would be hard to manage and is probably best enjoyed in natural areas.  However, we can bring some of the native colors of fall into our landscapes in a much lower maintenance, refined manner with two Panhandle species that pair excellently together, Muhly Grass (Muhlenbergia capillaris) and Darrow’s Blueberry (Vaccineum darrowii).

Muhly Grass and Darrow’s Blueberry in a local landscape. Photo courtesy of Daniel Leonard.

Muhly Grass, the native grass with the pinkish/purple panicles blooming right now, has gained much popularity in recent years, earning a reputation as a near pest/disease free, drought tolerant, attractive landscape plant.  Operating in lieu of more traditional low growing shrubs in landscapes, Muhly is an airy, greenish gray bunch grass growing about 3-4’ tall and wide, lending informal, coastal texture to landscapes most of the year and really shining in fall during its flowering season.  Once established, it never needs extra water, prefers little fertilizer, and only needs a rejuvenation prune (or burn – the Leonard preferred method.  It’s fun and mimics the role of fire in Muhly’s native ecosystems!) every couple of years to keep it looking tidy.

Unlike Muhly Grass, Darrow’s Blueberry has not caught on broadly in the landscape industry but is no less deserving.  This native blueberry species only grows a couple of feet tall, produces edible fruit that wildlife enjoy, and adds an unusual blue green color to landscapes via its tiny-leaved, evergreen foliage.  It prefers the same sites as Muhly and is part of the reason they pair so well together.  Our mostly sandy, well drained soils work just fine, but both plants can handle soils that are occasionally wet.  A bonus, Darrow’s also has tiny, bell shaped flowers in spring that attract all manner of beneficial bee species.  This makes it a must in any native pollinator garden!

As good as these species are alone, I think they are better together.  In my family’s yard, we created a loose screen of widely spaced (8’ apart) Muhly Grass specimens around a pool, in the spirit of giving the area a “coastal” airy feel, and interspersed Darrow’s Blueberry in between.

The pink Muhly Grass flowers pair nicely with the green blue foliage of Darrow’s Blueberry. Photo courtesy of Daniel Leonard.

The look has been outstanding, particularly in the late summer/early fall.  The pinky purple flowers of Muhly Grass complement the green-blue foliage of the blueberries nicely and provide easy, lasting color without having to worry about planting finicky annuals or perennials each season.

Landscaping with natives does not have to look wild and unkempt, nor does it have to be drab and unattractive.  Combining native yet showy plants like Darrow’s Blueberry and Muhly Grass makes for an unusual, refined, nearly no-maintenance feature in your landscape.  Look for these and other neat native plants at native nurseries and independent garden centers around the Panhandle.  If you’d like more information on native grasses, blueberries or any other horticultural topic, please contact your local UF/IFAS County Extension Office!  Happy Gardening!