Posts tagged leaves

Slimy slugs

Laura Jesse, of Iowa State University Extension’s Plant & Insect Diagnostic Clinic, wrote the following about garden slugs:

 

Slug photo by Laura Jesse of ISU Extension

Slug photo by Laura Jesse of ISU Extension

    There seem to be plenty of slugs in my garden, but I hope not in yours. Slugs leave small, irregular holes all over the leaves of plants. They especially seem to like my hostas but they are not picky feeders. Slugs are difficult to detect because they feed only at night. Slugs look like snails without a shell. They vary in size from less than an inch up to 2 inches in length, grayish colored, and a bit slimy to the touch. In fact as they crawl along they leave a slime trail.

    Slugs need moisture to survive and are found under mulch, rocks, logs, and other damp locations. My hostas tend to be eaten because they grow in a garden that is shaded and holds the moisture longer.

    Reducing slug damage is not an easy task and nothing will fix holes already there, so your first question should be – how bad is this and can I live with the damage? If you do decide to try to reduce the slug population you should combine several tactics. First, remove mulch and reduce moisture from around the base of afflicted plants as much as possible. Remove slugs you find either by using a trap such as a board on the ground that slugs will gather under or pan traps with beer as a bait. I assume cheap beer works fine and would not waste expensive beer on this. Remove dead slugs daily or it will get pretty disgusting. Finally there are commercially available slug baits available containing a molluscicide, but they are best used in the spring or fall.

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Good vs. Evil: Asian lady beetles and Japanese beetles

Asian lady beetle

Asian lady beetle - a good bug (photo/Cindy Hadish)

Their names are similar and they’re from the same region of the world, so I can see why some people are still confused about Asian lady beetles and Japanese beetles.  But when it comes down to it, there’s really no comparison. The bug pictured here – the reddish/orange lady beetle, is a beneficial insect. It feeds on aphids and other plant pests and doesn’t destroy anything, though I realize some people resent their intrusion in homes in the fall. On the other hand, the copper-colored Japanese beetle, a recent foreign invader in Iowa, is known to devour at least 300 plants, including hollyhocks, roses, raspberries, linden trees and grapes. If you see your leaves turning to lace, the likely culprit is the Japanese beetle.  Japanese beetles have no known predators here, other than me. So feel free to get rid of as many as you can. As mentioned previously, the most environmentally friendly method is to knock them into a bucket of soapy water when they’re sluggish – early evening seems to be the best time. If you have other suggestions – maybe from our East Coast readers and others who have learned to cope with Japanese beetles – please add your comments below.

Japanese beetles (photo/Cindy Hadish)

Japanese beetles - not a good bug, or just plain evil? (photo/Cindy Hadish)

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Ash trees, anthracnose and Emerald Ash Borer

Linn County Master Gardener, Claire Smith, shares the following about anthracnose and Emerald Ash Borer:

    Anthracnose – big word, hard to wrap your tongue around.  Anthracnose is a common foliage disease of shade trees in Iowa, including the ash tree.  Multiple inquiries to the Master Garden Hort-Line this morning were from folks whose ash trees were dropping leaves, an unusual occurrence in the spring.  A good guess would indicate that most of those folks were concerned that their wonderful ash tree had become infested with the Emerald Ash Borer.   Be aware that experts are seeing if the Emerald Ash Borer has invaded Iowa by crossing the river into the Northeastern portion of the state.

    A bit about each of these diseases: 

    Ash trees can be infested with anthracnose that is caused by a fungus.  There are a number of closely related fungi, but each is host specific to the tree it infects.  Often symptoms appear serious, but generally the damage caused is minimal and doesn’t seriously affect mature shade trees.  Symptoms include tan to black blotches; immature leaves becoming distorted from abnormal leaf expansion; young leaves dying and falling soon after a heavy infection.  If a severe infection does occur early in the growing season, the trees may defoliate and then a new set of leaves may emerge.  Following are some suggestions to decrease the severity of anthracnose and minimize its impact on your tree’s health:

–          Clean up and destroy fallen leaves:  use your lawn mower bagger

–          Prune the tree to remove diseased branches and properly dispose of them.

–          Prune to open the canopy for better air circulation. Fungi relish damp conditions. Pruning is generally not recommended now, but better to prune than lose the tree.

     The Emerald Ash Borer prefers Green Ash and Black Ash Trees, but will tackle any ash when the previous two mentioned have all been killed.  The borers emerge from early spring to late summer, but evidence may not be visible for up to a year.  Signs of infestation are D-shaped holes in the bark of the trunk and branches and shoots growing from the base of the tree which is the most telltale sign.  The beetle will effectively girdle the tree.  

Following are some suggestions to help reduce infestation and impact of the Emerald Ash Borer:     

–          Avoid planting ash trees

–          Learn the signs and symptoms of the Emerald Ash Borer

–          If camping, purchase firewood at or near the campsite but thoroughly inspect firewood prior to purchase

–          Do not bring extra firewood home with you.

     Maintaining a healthy environment for your trees and plants is of utmost importance.  A routine inspection of your yard and garden is necessary.  Discuss abnormalities with your local extension service, Master Gardeners, or a reputable garden center.  Pictures or actual plant samples are wonderful aids in diagnosing problems. 

REMEMBER THE LINN COUNTY MASTER GARDENER PLANT SALE THIS SATURDAY, MAY 16TH FROM 8:00 TO NOON IN THE EXTENSION OFFICE PARKING LOT AT 3279 7TH AVE. IN MARION.

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I Spy

Linn County Master Gardener, Claire Smith, submitted the following about springtime preparations:

 

I spy, with my little eye, something green.  It’s tiny, a sliver, and there’s another and another right there in my yard.  Under the melting snow and ice, live grass is trying to peek through.  Is it my imagination to expect green grass in early March?  As soon as we endure the annual State Girls’ Basketball Tournament snowstorm, it will be spring in Iowa!  Then, we can dig into yard work. 

Initially we monitor the gardens’ environments.  Disease prevention can save future headaches.  Start by removing unwanted leaves, branches and other debris deposited by wind or critters. Prune or trim back the stems you left for winter interest.   Peruse your garden catalog for species and varieties that are disease resistant.  Know if your new plantings prefer shade or a sunny setting.   Plan plantings to provide adequate airflow.   Humidity and wetness under the canopy are often conducive to disease so spacing is important. Maintaining good plant vigor through proper watering and fertilizing will make your plants less prone to disease.  As you plan your garden, consider the water source.  How many trips will you need to make with a watering can or how far will you have to drag a hose?  Is a rain barrel feasible in or near the bed?  How about a soaker hose?  I have two beds near the road ditch.   I alternate running the soaker hoses from a spigot beside the house.  I also have a water barrel mounted in a wagon to use for beds where no running water is available.   Proper timing with fertilization will be important.  Follow label directions on packages.   Retain the water and feeding directions for further reference. 

Compost amends the soil.  Use it abundantly!  Mulch is a valuable asset.  It helps hold moisture, chokes out weeds and prevents too much water from splashing on the underside of plants during a heavy rain.  I stock up my season’s supply as soon as each becomes available.

 Bird houses are a wonderful addition to a garden.  A water feature will attract birds and butterflies.  Both come in all manner of shapes and size. 

Remember to check out the rakes and shovels and tune up the lawn mower.  As soon as the soil is above 50 degrees, it’s time to plant!  

 

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California Dreamin’ – tree style

The following is by James Romer, Extension Horticulturist at Iowa State University:

   This time of the year gives many gardeners an empty feeling. It is hard to keep warm and dry when temperatures dip below zero and it snows every other day. It is reminiscent of those classic song lyrics — “All the leaves are brown and the sky is gray … California dreamin’ ….” Anyway, this is a great time of the year to do some planning and pruning.

   The late dormant period (February to early April) is an excellent time to prune deciduous trees. The absence of foliage at this time of year gives the home gardener a clear view of the tree and allows him/her to select and remove appropriate branches.              

   Proper pruning improves the appearance, maintains the health and prolongs the life of trees. Improper pruning destroys their natural beauty, weakens them and may lead to their premature death.

   It is essential to make proper cuts when pruning trees. Do not make flush cuts. Flush cuts are cuts made as close as possible to the trunk or main branch. Flush cuts produce large wounds, destroy the tree’s natural mechanisms that promote healing and slow the “healing” process.

    When pruning trees, make the final cut just beyond the branch collar and branch bark ridge. The branch collar is the swollen area at the base of the branch. The branch bark ridge is the dark, rough bark ridge that separates the branch from the main branch or trunk. Pruning just beyond the branch collar and branch bark ridge retains the tree’s natural defense mechanisms and promotes the healing process. When a branch is pruned properly, a slightly raised area remains on the trunk or main branch. However, do not leave stubs.

   Do not apply wound dressings to pruning cuts. The application of wound dressings or paints doesn’t stop decay and may actually inhibit or delay the healing of wounds.

   There is one exception with not applying paint to oak trees. Oak wilt is a fungal disease that is lethal to many oaks. Oak wilt infections occur most commonly in spring and early summer and are spread from infected trees to healthy trees by sap-feeding beetles. To reduce the risk of the spread of oak wilt, don’t prune oaks from April 1 to July 1. If oak trees must be pruned between April 1 and July 1, for example, to correct storm damage, immediately apply a latex paint to all cut surfaces to avoid attracting sap-feeding beetles to the wounds.

   Use the three-cut procedure when cutting large branches to prevent extensive bark damage. Make the first cut about one to two feet from the main branch or trunk. Cut upward and go about halfway through the branch. Make the second cut a few inches beyond the first. Cut downward completely through the branch. Make the final cut just beyond the branch collar.

   Some trees, such as maple, birch and elm, bleed heavily when pruned in late winter or early spring. However, the heavy bleeding doesn’t harm the trees. (The trees won’t bleed to death.) Eventually the flow of sap will slow and stop. Heavy bleeding of susceptible trees can be avoided by pruning in late June or early July.

   The pruning of deciduous trees by the home gardener should be limited to small trees and the removal of smaller branches that can be reached from the ground in medium to large trees. Branches high up in large trees and those near utility lines should be left to professional arborists. Professional arborists should have the proper training and equipment to safely perform the job.

    If that’s not enough to do, another enjoyable winter activity is to leaf through garden catalogs. Many contain colorful plant photographs. Some carry specific merchandise, such as seeds, perennials, roses or fruits. Others carry a wide variety of products.

    Also, visit a bookstore or public library and browse through some of their gardening books. Excellent reference books for home gardeners include “Manual of Woody Landscape Plants” by Michael Dirr; “Continuous Bloom” by Pam Duthie; “Herbaceous Perennial Plants” by Allan Armitage, and many others.    

    Remember also that your Iowa State University Extension county office has numerous publications on gardening in Iowa. Most of these publications also are available from the ISU Extension Online Store at www.extension.iastate.edu/store.

So get busy planning, pruning and dreaming about plants for this spring.

 

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Wood vs. rock

Linn County Master Gardener, Claire Smith, offers the following on mulch choices:

      While you’re contemplating donning your thinking cap to plan another flower garden, here’s an interesting comparison by Linn County Master Gardener, Deb Walser  recommending mulch over rock.

     Display beds are often mulched with mulch fabric then covered with rocks.  It is believed this is maintenance-free.  However, after a few years, leaves, dirt and other debris will land in the rocks causing a buildup of organic material.  Weed seeds may then blow in and start to grow in this fertile soil bed.   Often the solution to this problem is adding more rock—which only compounds the problem.  Also, this is not a suitable planting medium for annual flowers.  Rocks must be pushed back and holes cut into the fabric for plant placement.

      Both mulches help hold moisture in the soil during an average spring.  However, in the summer, with higher temperatures, rock pulls valuable moisture, needed by the plants, away from the soil.  Rock does not improve the soil in any way.

      I recommend the use of wood mulch for all beds and borders.  It holds back weeds, holds in moisture and as it biodegrades, helps improve poor soil (i.e. clay).  When soil, leaves and debris land in a wood mulch bed, it becomes part of the soil.  The only disadvantage to wood mulch may be that top dressing, (applying a thin topcoat) may be necessary each spring to maintain the aesthetic appeal, and to fill in any areas where it may have moved or decomposed.

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Grandma’s plants

     The following is from Linn County Master Gardener, Claire Smith:

 

     Did you get Grandma’s Christmas list?  I’ll bet she says she doesn’t want anything:  she has too much stuff already.  What do you do?  How about a winter blooming window sill plant!

     There are some really neat little fellows out there.

·         African Violet:    has soft thick leaves and beautiful petite blooms.  Enjoys temperatures around 70’ with good air circulation.  Likes about 16 hrs. of daylight and 8 hrs. of darkness each day to produce blooms.  Hmmmmm sounds just like my Mom, warmer temps. and a good night’s sleep!

·         Shamrock:  resembles a large clover. Can have green leaves but can also be tricolored or deep purple.  Desires cooler temperatures, around 65’ and lots of bright light.  Grandma will be lucky to receive this one.

·         Spider Plant:  enjoys bright light and temperatures around 65’.  Mine profusely  grows long slender leaves with tiny white flowers in a sunny Northwest window.   Pebbles and water in a saucer under the plant offers humidity, keep the roots away from the water though.

·         Cyclamen:  heart shaped leaves and papery soft petals blooming in winter.  Wants well drained soil, really cool temperatures, i.e. 55’ and indirect light.  Great for an area without a lot of windows.  

    If Grandma would prefer a larger plant try:

·         Peace Lily:  not for the faint of heart, this plant has the capacity to become huge. Use it to fill an empty corner.  One of the first plants I ever had, I can attest that the Peace Lily will survive well in almost any condition.  Prefers bright, filtered, or natural light.  Has abundance of glossy, green foliage and regularly produces dramatic white blossoms.  Enjoys any comfortable room temperature.  Soil should be kept evenly moist.

·         Norfolk Island Pine:   Grandma gets a small live Holiday tree with this one.  Let the grandkids have fun decorating with lightweight ornaments.  Thrives with consistent care.  Needs brightly lit window.  Rotate weekly as it will grow toward the light.  Water thoroughly when soil becomes dry to touch. Discard excess water from saucer.  Likes humidity:  place on a pebble tray.  Likes temperatures 55-70’. 

    Complete your choice with a colorful bow and a handmade card and Grandma’s gift will be indeed special! 

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