Brian Boesch, Graduate Research Assistant URI

Vol. 1, No. 3
September 2005
Brian Boesch, Graduate Research Assistant
URI - Department of Plant Sciences
Velvet bentgrass (Agrostis canina) has always
not managed properly. Velvet is adapted to low pH soils: pH
intrigued golfers with its extremely fine texture. Ironically, it
5-6 being ideal. Traditionally considered a low maintenance
has never been planted extensively or studied in great detail.
turf, velvet is well-known for looking good with much less
Even though it has not been widely accepted, exceptional new
input. However, this is not necessarily always the case. Seed
varieties of this grass have been developed over the past 20
is available for four velvet cultivars: SR7200, Greenwich,
years but proper management of the grass can still be
Vesper and Legendary. A few newer varieties are currently
confusing.
under NTEP evaluation but are not yet available for purchase.
History: Velvet bentgrass was introduced to the
Management: There is not much information about
United States over a century ago. It was imported from
velvet bentgrass management in the scientific literature. Much
Europe, and sold to New England growers as South German
of what we know today has been passed down anecdotally
Bentgrass (a mixture
through generations
of creeping, colonial,
of people growing
redtop, and velvet
this grass. In the
bentgrass seed).
1960’s through the
Turfgrass breeders
early 1990’s, Dr.
eventually isolated
Richard Skogley
clones of the grass
worked on velvet
from
naturally
bentgrass at URI
growing patches of
and
published
velvet bentgrass turf,
articles on its
however, it was
management. Based
difficult to propagate
on his fertilizer
because of poor seed
recommendations, a
production. Most
nitrogen rate of
early cultivars of Photo of 2-year old SR7200 velvet bentgrass green with a sand rootzone. Each plot recieves different rates more than 2 to 3
velvet bentgrass of fertilizer and cultivation. The tan to yellow colored plots receive little or no fertilizer. The highest rate l b s . / M / y r .
was
of fertilization is 5 lb. N/M/yr. This green is mowed at 0.115” with a flexmower.
could
only
be
thought to be
established vegetatively. This problem limited its availability
excessive and would ultimately lead to significant thatch
to turf growers. Complicating things further, velvet never
accumulation, disease problems, and an overall decline of the
behaved like the more prominent creeping and colonial
turf. These observations were based on the turf management
bentgrasses and it did not survive well using traditional
environment, equipment capabilities and available varieties at
creeping bentgrass management strategies. Today, velvet
the time. In addition, mowing heights were higher and sand
bentgrass is distributed across the northeastern and
greens were less prevalent during the earlier studies. The
northwestern portions of the U.S. (mainly on golf courses),
belief that velvet bentgrass is “low maintenance” is not
and throughout Europe. Year after year, golfers still rave about
entirely true when you factor in current turf management
its beauty when compared side-by-side to the other
strategies and practices.
bentgrasses.
For the past 2 years, we have been investigating turf
Characteristics: Velvet seed germinates relatively
quality and thatch accumulation under many different cultural
quickly - often in 5-7 days. Leaves are ultra-fine; 1-2 mm
management conditions on velvet bentgrass greens at the URI
wide at maturity and low heights of cut. While the grass does
Skogley Memorial Turf Research Facility. The management
produce small stolons, it actually spreads laterally very slowly.
conditions tested include: fertilizer rates, topdressing &
It prefers to grow vertically and tillers wildly, acting much like
vertical mowing practices, sand vs. silty-loam rootzones, and
a bunch-type turf. The most remarkable quality of this grass is
SR7200 vs. Greenwich velvet bentgrass. The full report of
its exceptional density. Velvet bentgrass is the densest
this research will be released next year when the project is
growing turfgrass known, and produces almost twice as many
completed. The following sections list some useful velvet
leaf shoots (approx. 2,500 shoots/ft2) than its closest creeping
recommendations based on our own trials and advice from
bentgrass cousins. All this extra grass can become thatchy if
other velvet growers.
Fertilization. For the highest quality greens on sand,
This grass seems to have a better tolerance for lower cutting
at least 4 lb. N/M/yr. should be applied to sand-based greens
heights than creeping bentgrass. In addition, mower reels
but 5-7 lb. N/M/yr. is a more realistic figure in our region. 3-4
should be sharp to get clean cuts. The turf surface declines if
lb. N/M/yr. is fine for velvet growing on finer textured soils.
grass is torn or ripped by dull reels.
Application rates should range between 0.1-0.5 lb. N/M,
I r r i g a t i o n . Velvet has a much lower
applied every 1 to 2 weeks depending on need. Liquid
evapotranspiration rate than creeping bent, requiring a lot less
fertilizers give much better results than granulars, which
water. Specific watering needs will vary depending on soil
produce uneven splotchy areas as they cannot penetrate the
and environmental conditions. Compared to creeping
thick canopy evenly. Granulars do work well when used for
bentgrass, velvet is certainly “low maintenance” in its demand
spring greenup. Use acidic fertilizers to help keep soil pH low
for water. Excessive moisture, particularly a problem on
and stay away from ureas, nitrates, or other alkaline fertilizer
push-up soils, can often increase thatch significantly.
formulations. Ureas and nitrates can raise soil pH around
Pest Management. Velvet bentgrass has high
turfgrass roots and
resistance to Dollar
lead
to
Spot; only in rare
micronutrient
instances will it
imbalances for
show up on velvet.
velvet, potentially
Copper
Spot,
inducing chlorosis.
Pythium, Brown
Velvet responds
Patch, Pink Snow
well to iron, most
Mold, and Fusarium
micronutrient
Patch diseases are
The sample on the left is from our 2-year old velvet sand green. The sample on the right is from a pushup
products,
a n d type, silt-loam soil green established 2 years ago from sod. The red line marks the thatch-soil interface. Both more common on
wettable sulphur. samples receive the same level of fertility, about 5 lb. N/M/yr. Our sand green is just beginning to show a velvet. Use legally
thatch layer, even though we do not topdress or vertical mow as often as we should. The level of thatch
Stay away from small
labelled fungicides
in the silt-loam soil green is excessive and attempts at vertical mowing cause significant damage. Damage
lime, copper or recovery on this green is then severely impaired by the excessive thatch.
to combat these
other alkaline
diseases. Weeds are
chemicals. If you see chlorosis, spray a high rate of chelated
generally not a big problem on velvet because of its density.
iron (3-5 fl.oz., 9-12% iron solution) to correct the problem
However, be mindful that aerification and vertical-mowing
but work on lowering pH as well.
will introduce weeds. We have tested a few postemergent
Topdressing & Vertical-mowing. Thatch
herbicides (VelocityTM & QuicksilverTM), and velvet has shown
accumulation is a huge problem with velvet because there are
very good tolerance even at .115” HOC. However, we do not
so many plants so close together. Vertical mowing should be
recommend applying these herbicides to greens without proper
performed at least once per month and a light coat of
labeling. VelocityTM is currently not labeled for use on greens.
topdressing must be applied every 2-3 weeks. In our study,
Final notes. Since velvet does not grow laterally very
thatch accumulation was not significant after 1 year in any
well, it’s a good idea to keep some seed on hand to repair
trial, however, our sand-based velvet green remains virtually
damaged areas. If you’re purchasing velvet sod, make sure
thatch free after 2 years. Our silt-loam soil green has a thatch
it’s not too old and doesn’t have a lot of thatch, which can be
layer 1-3 cm deep, its original sodded depth. Velvet greens
extremely difficult to remove in a short time and still maintain
with excessive thatch are extremely prone to injury from all
playability. Sand greens will minimize thatch in velvet. Keep
sources of environmental and mechanical stress. Velvet is
in mind that putting greens are high maintenance turf and
almost impossible to manage if it becomes excessively
velvet bentgrass is no exception under normal circumstances.
thatchy. When velvet greens do become excessively thatchy,
But while it does need as much nitrogen as creeping bentgrass,
the best suggestion is to drop the box blade and drag every
it is “low maintenance” when it comes to both water demand
square inch off the golf course.
and disease susceptibility.
Mowing. Velvet should be cut low. Higher cuts will
inevitably induce thatch and will be more difficult to maintain.
The URI Golf Course Superintendents Factsheet is a
If possible, use walk-behind flexmowers: these give the best
publication of the URI Turfgrass Disease Diagnostic
results. On greens, velvet should be mowed to 0.110”- 0.125”
Laboratory. We can be reached online at www.uriturf.org
(using a flexmower) and may do well at even lower cuts.
and by phone at 401-874-5996. Brian Boesch can be emailed
Generally, the lower you mow, the denser velvet will grow.
at [email protected].