Wednesday, September 30, 2015

Aspens on the Plains

Pictures by Linda Langelo, CSU Extension Horticulture Program Associate

Populus tremuloides, Aspen have their own beauty.  The only tree close to this striking white bark is Paper Birch, Betula papyrifera.  Paper birch does not tolerate drought.  Aspen trees live in altitudes well above the normal range on the plains which is 3,500 to 4,500 feet.  But once Aspens are well established on the plains of eastern Colorado as those in the above pictures, they tend to do well.  The trees pictured above were placed by a swimming pool for many years.  The pool is now gone and they are still doing well.  They survived the last three years of extreme drought.   These are not trees recommended for eastern Colorado, but people fall in love with their beauty.  The danger is planting trees outside their normal range whereby they succumb to diseases and insects and keeping them in good health is challenging because the environment they need is not available to them.

Monday, September 28, 2015

Water, Water, Water

Picture by Linda Langelo, CSU Horticulture Program Associate

As summer comes to a close and fall begins, remember to water the grass during extended dry periods in both fall and winter.  This will help to prevent root damage.  Healthy roots makes for a healthy turf. 

Speaking of roots, now is a great time to fertilize your turf.  Fertilizing your turf now can help your turf in the following ways:  better color through the winter and earlier spring green-up.  The turf will have an increase of carbohydrate reserves along with improved fall, winter, and spring root growth. Lastly, the turf will have increased shoot density.  Two of the possible side effects of doing fall fertilization is the increased chance of snow mold injury and decreased cold tolerance of your turf.  It can happen.  I prefer better root development over spring fertilization causing an increase in top growth with a root system that might not be able to support the top growth.

During the growing season the best time to irrigate your turf would be between 10 pm and 6 am.   The next best time is from 9 am to 11 am.  If you are forced to irrigate between 9 am and 4 pm just remember that the sun and wind can cause additional water loss. 

The following cool season grasses need regular applications of water:

  • Bluegrass
  • Fescue
  • Perennial Ryegrass
  • Bentgrass
Kentucky bluegrass will need 2.5 or more inches of water per weekly application of water during the hot summer months.

Help the Monarch Migrate

Picture by Linda Langelo. CSU Horticulture Program Associate

Here in Sedgwick County, Colorado in our community garden the monarch has stopped along the way to refuel on an okra flower before continuing the migration south to Mexico. 

Monarchs are disappearing because of the destruction of Milkweed.  Milkweed is the critical plant where the adults which fly north in February and March lay their eggs on milkweed.  The young caterpillars feed only on the milkweed.  This is what we call host specific.  The host is milkweed food for the monarch caterpillars.  There is no second choice or other preference.  They depend on each other.

The monarchs which fly south to Mexico for the winter are not the same as those that return.  Those that return are the fourth generation.  All the other generations are first through third which live only 2-6 weeks.  The fourth generation lives 180 to 240 days which is about six to 8 months.  They can also hibernate in California as well as Mexico. 

Fill Your Landscape with Natives


Pictures by Linda Langelo, CSU Horticulture Program Associate
The first and second picture from the top is Ratibida pinnata, Prairie Coneflower.  The bottom picture is Monarda fistulosa, Wild Bergamot. These plants need very little to no care and both are perennial.  They do not need fertilization.  They do not need deadheading to keep producing. 
Ratibida starts blooming in June and lasts through October.  Monarda starts blooming in July through October.  These plants are great additions for fall color in your landscapes. 

Eight Spotted Forester

Picture by Linda Langelo, CSU Horticulture Program Associate

What is eating my grape vines??  This is the eight spotted forester, Alypia octomaculata which turns into to a striking adult black moth with yellow and black spots.  It is not a serious pest.  They also feed on Virginia creeper and grape vines east of the Rockies.   They chew the leaves from early June through August.  They have two generations a season.  One generation occurs in May and one occurs in August.  They winter in the pupa stage in a cocoon in the soil.  These insects are as colorful in the caterpillar stage as an adult.  The caterpillar is a pale blue, well patterned with rows of black spotting, orange banding along the side, and a rounded hump on the hind end. 

Thursday, September 10, 2015

Trees that succumb to freeze damage

Ornamental Pear picture by Ken Gierhart

Sometimes trees show very visible signs of freeze damage and sometimes we do not get to see any visible damage.  Two tips which can help avoid some of this damage:
  1. Do not do any late summer pruning
  2. Do not do any late summer fertilization
Both of these activities list above stimulate tender new growth which may not have enough time to harden off properly before a freeze.  We have to watch for early freezes in the fall and even late freezes in the spring.  Anytime the weather warms up enough to stimulate new growth, it can be damaged.

None other than Cat-faced Spider

                                  Picture by William Ciesla of Forest Health Management International

This is a photo of a cat-faced spider.  Their webs are a concentric design which they relocate regularly.  The web is located on vegetation a few feet above ground level.  The web is used to capture their prey.  The web is consumed and reconstructed often.  This fall the female cat-faced spiders will be laying eggs their which overwinter within a silk-covered sac.  The full-grown females are most often seen.  The males are half as large as the females.  Their sizes vary from 5-7 mm long and 4.5-5.5 mm wide.  Coloration varies widely from straw-colored to dark grayish brown. 

Thursday, August 6, 2015

Photo by Linda Langelo, CSU Program Horticulture Associate
We did it again!  The Burlington Garden Club chose the Burlington Community Garden as garden of the month.  Recently we put fabric down for our paths around the raised beds and then pea gravel to cover the fabric.  It is easy for folks to garden in a 4 x 4 foot square.  Some folks have more than one square while others have one square they manage.   We are getting ready to place new covering on the greenhouse. 

Cultivated plants turned aggressive

Photos by Elizabeth Thomason
Plants like Bouncingbet, Saponaria officinalis, where once used in our gardens.  A seemingly wonderful plant with its great attribute of exceptionally hardy and drought-tolerance has become a nightmare to control.  Still sold commercially as seed and still making its way into landscapes.  This European plant once used as a soap substitute is now aggressive and disruptive to our natural habitats in many states other than Colorado. 
To think that this plant along with many others was sought by gardeners to have as a prized specimen in their landscapes.  Another prized specimen is Lythrum salicaria, Purple Loosestrife.  The seeds of these pink flowering plants can wash easily into waterways.  The root system of Purple Loosestrife will resprout from any remaining root fragments.  This makes it even more difficult to control. 
For Colorado you can go to the following link and look to see if you have any of these plants in your landscape:

Monday, July 27, 2015

Is this happening to your trees?

Photos by Linda Langelo, CSU Horticulture Program Associate
The condition in the above pictures is an iron deficiency.  Along with the iron a leaf scorch is sure to follow.  There are many reasons for an iron deficiency among which is compacted soil, soil that is too wet or too dry.  If  the pH of the soil where the tree is planted ranges above 7.0 into 7.2 and 7.5, then this condition begins.  Take a soil test before you decide which type of tree you can plant in your landscape.  Along with crabapples, maple trees are also very susceptible to iron deficiency.  Without adequate iron, the tree cannot complete the photosynthesis cycle.  So the tree ends up not getting a good supply of sugars and starches.  Applying chelated iron is helpful.