Move Over Pentas.......Vinca Is Back!!

Move Over Pentas…….Vinca is Back!! 

     

Vinca Cora Cascade 'Cherry Red'  (Venetian/Palazzo)

The use of Vinca or Periwinkle as a summer annual in the Las Vegas Valley has declined significantly over the past 20 years.  Most recently, the use of Vinca has been limited to residential landscapes with very little use in commercial applications.  The reason for the decline has been the plant’s susceptibility to 'Aerial Phytophthora’ also known as ‘sudden death’ disease. 

Vinca Cora 'White'
(Venetian/Palazzo)

Aerial Phytophthora is a soil-borne fungus that is often referred to as a water mold since it is most often associated with wet poorly drained soils.  The fungus  produces zoospores from sporangia that swim in water films or may be splashed from the soil surface to plant foliage where initial infection occurs.  The disease causes the leaves to collapse as it progresses down the petiole to the stem (node) where it kills the tissue producing a sunken lesion, followed by the stem also collapsing.  Symptoms of collapsed leaves are evident in a few days of infection with loss of the entire plant within one to two weeks.  Due to difficulty of control, which usually involved fungicide applications (foliar/drench), crop rotation, etc. and the increased availability of new warm season annuals including Pentas, Vinca quickly lost its popularity. 

Vinca Cora 'Burgundy'

The loss of Vinca from Las Vegas summer landscapes was huge!  This was a plant that could thrive in heat while producing almost a tropical effect with its dense dark green glossy foliage and masses of long term blooms of a wide variety of colors.  However, this summer the homeowner will see a new Vinca, one that has undergone a new makeover.  The new plant will be called Vinca ‘Cora’ and will be Phytophthora resistant!

Vinca ‘Cora’ is a new series F1 hybrid developed by Goldsmith Seeds and has taken over twenty years to develop.  Eight colors are available including Apricot, Burgundy, Deep Lavender, Lavender, Pink, Punch, Violet, and White.  Mature plants reach 14-16 inches in height with a 22-25 inch spread.  Vinca ‘Cora’ has been used commercially for a couple of years, including at the Venetian Palazzo Resort, starting in the summer of 2009 where it proved to be a huge success.  Up until now the availability of Vinca ‘Cora’ has been somewhat limited to the homeowner.    

Vinca Cora 'Deep Lavender'

In addition to the standard Vinca ‘Cora’ Goldsmith Seeds has also developed Vinca ‘Cora’ Cascade!  This has proven to be a wonderful flowering plant for hanging baskets, pots, or anywhere bright colored flowers in a cascading form in high heat environments is desired.  New colors include Lilac, Magenta, Peach Blush, Polka Dot, and Cherry Red.  Cherry Red proved to be an exceptional performer at the Venetian/Palazzo Resort.   

Watch for these great new Vincas late spring early summer in your local nursery and garden centers.  

Landscape Management Programs for HOA's

Landscape Management Programs for HOA’s

                                                               

During the past thirty years I have had the opportunity to work with many different Homeowner Associations in terms of landscape maintenance and management.  This has involved onsite troubleshooting of plant and irrigation problems as well as developing site specific landscape management programs.    

A good landscape management program not only meets the day to day upkeep required of landscapes, but also ensures long term health of plants and overall aesthetics.  A good site specific landscape management program will help in keeping maintenance costs down while keeping long term property values up. 

In the Las Vegas Valley each HOA Development, of condominiums, townhouses, or single family residences, common area landscapes of each are often unique.  Landscape use or function often varies from property to property as well as plant  types, soil types and conditions, and micro/macro climates that create the landscape environment.

Landscape management programs can be provided or developed by a landscape maintenance company or the Homeowners Association.  Most landscape maintenance or landscape management companies utilize landscape maintenance programs in maintenance of their properties.  Most often the programs are generic although a few landscape management companies may provide site specific programs. 

A few years ago I was asked by a Homeowners’ Association to assist in selection of a landscape maintenance company to maintain their condominium development.  The HOA was experiencing a high turnover in landscape maintenance contractors which resulted in a negative impact on the condition of the landscape.  The HOA did not have a site specific landscape maintenance program and was dependent on each contractor to provide a generic program with their bid.  In addition, there was not any agreed upon ‘standard level of maintenance’; therefore, bids submitted by contractors were wide spread ranging from $3,000 to $5,000 per month and each time the HOA would accept low bid.  Awarding the contract to low bid is acceptable if the difference between the low and high bid are close and fall within an acceptable range. To help this HOA it was necessary to develop a site specific landscape maintenance program that would become an integral part of the bid and contract specifications.  For the first time contractors were bidding ‘apples to apples’.  Bids came in at $3,800 to $4,100.  At first glance, the $3,800 may seem considerably higher than $3,000, but as I once heard a wise landscape consultant say at a landscape maintenance conference, “it costs, what it costs, what it costs”.  Landscapes are expensive to install and when properly maintained improve the quality of our lives and increase the value of our property. 

Site specific landscape management programs also place control for both short and long term landscape health and aesthetics in the hands of the homeowners and the property management company.  Landscape cultural practices often involve the application of fertilizers, pesticides, and other chemicals all of which carry a certain degree of liability for the HOA and property management company.  Therefore, it is important to have the control necessary to provide not only an attractive landscape, but also a safe landscape. 

Turf Reduction - Problems For Some?

Young Ash tree displaying symptoms
of severe drought stress due to a
poorly designed irrigation system.

Turf Reduction  -  Problems For Some

In December of 2004 at the conference of the Colorado River Water Users Association a $200 million conservation initiative was announced to assist public agencies to save water through turf-reduction programs.  Southern Nevada Water Authority’s ‘Water Smart Landscape Rebate Program’ has since helped both homeowners and businesses in reducing landscape water use while creating aesthetically pleasing desert landscapes. 

In general, the rebate program has been a tremendous success.  However, there have been a few problems associated with the conversion of turf to desert landscape.  The most common problem involves maintaining the health of trees that once grew in large turf areas where they enjoyed high soil moisture levels, cooler soil temperatures and higher humidity and now find themselves in an arid environment.  Trees are one of the strongest and most important elements of a landscape and during any landscape conversion process their preservation should have a high priority. 

During the conversion process not only is the turfgrass removed, but so is the overhead irrigation system.  With the overhead turf irrigation system maintaining high soil moisture levels over large areas, mature trees could often expand their root systems beyond their dripline.  Conversions called for the replacement of overhead irrigation systems with a more efficient surface or subsurface drip-type system.  In most cases, the new drip-type irrigation system would not be designed to continue to provide coverage to 100% of a large or mature trees existing root system.  The new irrigation design concept would attempt to meet a minimum of 70% coverage of the existing root system.  Obviously, a 30% loss of irrigated root zone, especially the perimeter feeder roots, is going to cause stress to trees.  However, with care and proper cultural practices most trees will adjust and will continue to thrive.  However, when drip-type irrigation systems are not properly designed slow decline and loss of established trees may occur. 

Poorly designed irrigation
system caused drought
stress predisposing tree to
Sooty Canker (Fungus)

This past summer I consulted on several projects involving tree decline and death on HOA properties that had undergone a prior turf-reduction and landscape conversion.  Poorly designed drip-type irrigation systems were most often responsible.  Tree conditions ranged from healthy to severely stressed or even death.  In general, the healthier trees were also the smaller trees.  This was due to the trees having smaller root systems thus being less impacted by the reduced size of the new irrigation system as well as less root disruption or damage during installation.

Bark of dead branches
split open revealing a black
dusty mass of Sooty Canker
fungal spores 

Trees that are stressed due to insufficient irrigation are weakened and can become subject to a whole new set of problems.  Environmental factors such as sunscald or insect and diseases that previously were not an issue now become major problems.  A good example can be seen in the attached photographs of a Las Vegas townhome complex that had a few years earlier undergone a landscape conversion involving extensive turf reduction and the installation of a poorly designed irrigation system.   The photographs were taken late summer.  The previous fall and late winter we received rain and conditions were fairly moist.  This was followed by a hot windy summer.  During this time the fungus ‘Sooty Canker’ (Hendersonula toruloides) easily established itself in the weakened trees.  The disease in one season had severely damaged or killed most of the large ash trees. 

Throughout many areas of the Southwest we are seeing the use of turfgrass being reduced in landscapes with landscape designers now placing more emphasis on turf functionality.  Aesthetics is still important; however, we can still create attractive landscapes with less turf.  It’s also important that we continue to reduce the amount of established turf in an effort to conserve one of our most precious natural resources.  However, it’s also important to maintain the health of our large and mature trees during the process of turf reduction.