Down the Garden Path

Richard Hentschel, Extension Educator

New USDA Plant Hardiness Zone Map

USDA recently released a new Plant Hardiness Zone Map that really changes what Extension Educators have taught and what gardeners have come accustomed to when shopping for hardy landscape plants. The first question most gardeners have when looking for new landscape plants is "Is it hardy in our area?" The question remains very valid as you would not want to purchase a plant that will not survive our winter weather in the home landscape. Gardeners are willing to take a chance once in awhile with some of the broadleaved evergreens like Holly, Rhododendron, Boxwood as long as they can plant them early in the season and provide winter protection for the first several years and IF they have a protected location .

The old zone map used the data from decades past that created localized pockets within larger zones. This new hardiness zone map uses data from just 1976 through 2005 to create the current zones. This map, just like the old one uses average annual minimum winter temperatures to create the new zones broken out into 5-degree divisions. Gardeners will see that those smaller colder or warmer pockets are now gone. The small band of Lake Affect is still immediately west and south of Lake Michigan in Chicago.

In Illinois the zones range from 0 to 5 degrees at the very southern portion of Illinois to -15 to -20 degrees in the Northwest portion of Illinois. Kendall, Kane, and Dupage counties are in zone 5b with temperatures of -15 to -10 degrees for our winter range. We used to be in 5a, having temperatures 5 to 10 degrees colder during the winter. These new zones reflect the trends we are experiencing the last several winters, not as cold or the cold does not stick around and for extended periods limited or no snow cover.

This change in the zone map will mean it will take awhile for the horticulture industry to catch up with accurate hardiness zone map information on the plant tags. There have always been some differences in the industry, based on which zone map you were looking at. There has been the map from USDA and the other from Arnold Arboretum out east. Any plant rated in a hardier zone than us will survive our winters easily.

The new site is interactive, allowing you to put in your zip code to reveal the hardiness zone you live in and you can also print out individual state maps. Besides the 48 states you can check out Hawaii, Puerto Rico and Alaska. The web site is: www.planthardiness.ars.usda.gov

Down the Garden Path

Richard Hentschel, Extension Educator

Training your apple tree

Just what do experts mean when they say 'you need train your fruit tree?" Home orchardists need to train for tree structure to encourage fruit production to have a productive, high yielding home orchard. The branches need to be positioned to allow good sunlight throughout the canopy to promote fruit production from the interior to the outside of your tree canopy. This will also let air circulation in the canopy, reducing leaf and fruit diseases, so you benefit in two ways. Proper training also allows the fruiting branches to support the fruit load without additional support.

Using dwarf apple trees as an example, you will likely use what is called the central leader system to train your trees. The central leader system allows your fruit tree to look like most other trees in your landscape, yet produce apples without the tree looking like those you see in a commercial orchard. Training starts the first year you plant the dwarf trees. This will ensure your dwarf tree actually remains dwarf in your home orchard.

You will be able to start to select your scaffold branches placing the first set of scaffold branches no more than 24 inches from the ground. By starting that low, you will be able to place additional scaffolds and still have a mature tree that is no taller than 6 to 8 feet tall, making it very easy to manage. That may be too low to mow easily, so consider a large ring of mulch that extends to the edge of the canopy. This mulch ring can be increased in size as needed. If a dwarf tree is allowed to grow without being well trained, that fruit tree will be much larger that you planned for and fruit production will likely be delayed.

There are several other advantages of a well trained dwarf fruit tree. Annual Spring pruning will be visually much clearer as to what branches will need your attention. There will be branches that need to be adjusted using traditional branch spreaders or alternative methods such as using twine and a stake to pull the branch into the desired horizontal plane you need as you develop your scaffolds. Water sprouts are easily identified as they will be growing straight up from the horizontal scaffold branches. Foliage and fruit treatment will be much easier as the scaffolds will allow easy access to the entire canopy. Harvest is much easier and a lot more fun too.

As your dwarf fruit tree matures, home orchardists will realize there are additional benefits. The weekly inspection and monitoring of fruit pests will be easier and done very quickly. Even though young fruit tree may not be producing apples, there are insects and foliar diseases that need to be taken care of. Foliage feeding insects reduce the canopy, reducing the amount of food that could go into growing and developing. Leaf diseases have a similar impact. If allowed to continue over the season or seasons, it could easily delay fruit production and limit the number of high quality fruits you are able to harvest. You want a tree that develops quickly, yet one that you have trained to encourage flower and fruit set. Enjoy the challenge and amaze your friends with fruit that came right out of your yard.

Down the Garden Path

Richard Hentschel, Extension Educator

Snow on the Ground

Gardeners have certainly been justified in wondering what spring will be like with the mild winter we have been having. Plants in our climate need to have a cold dormancy period to begin growth properly. Seeds need a dormancy period as well to tell them it is time to break that dormancy and begin a different kind of life. Seeds are alive and need the winter to allow them to start to grow into plants.

Another concern has been without the usual snow cover in our area, the impacts of drying winter winds and exposure in general can have damaging effects on our perennials and ground covers. Without the snow, crowns of strawberries, rhubarb and our lawn grasses can be damaged. Snow is a great insulator for our plants. One good thing this winter has been without the snow and consistent below freezing temperatures we have had good amounts of moisture. Normally the dry winter winds would begin to desiccate the foliage and crowns of exposed plants.

There has not been much of a discussion yet about insects in 2012 in the home landscape. Insects that overwinter as adults exposed or hidden in cracks and crevices on the bark of trees and shrubs are able to withstand our typical winter weather, so this year there is not a question that that will be here this spring. Insects that are marginally harder here have had an easier time so far. How much more snow and how much more really cold weather will determine how many make it till spring.

Before the cold weather and snow hit us, the Master Gardeners and I got to see Snow Fleas brought in by a concerned resident who had never seen them before. Very small blue black colored insects that look a bit furry. They are part of the Springtail family and jump about in the same manner once they warm up. Why were they in the yard by the many thousands? Once again it has been our weather. It has been cold and moist just about everywhere, allowing the Snow Flea to exist and multiply in more places and for longer periods of time. Snow fleas are harmless and a homeowner would never likely see them, except this year. The same thing can be said for algae, mosses and fungus. All of these will retreat to their respective habitats and seemingly disappear as the weather warms and dries out late next spring.

Cold winter weather is necessary for all our landscape plants. Just as the cold fall weather signaled the plants along with the shortened days to prepare for winter, the end our cold weather signals the plants that spring is near and to get ready to break dormancy. Master Gardeners have received calls from homeowners finding their spring bulbs poking out of the soil, something that is a lot more common in March, not January. The tips of the leaves may be damaged, but the flower bud itself is still down in the bulb and will not be harmed.

Even though we have enjoyed clean open roads and have left the snow shovel leaning up against the wall until now, we really do need the snow cover for our landscape.

I am very pleased to post Richard's weekly news column in our Over the Fence blog.  This will be a great addition!  It will not only help keep the blog a little fresher, but we all get to read some very interesting articles.  Thanks for sharing, Richard!

Down the Garden Path

Richard Hentschel, Extension Educator

What's in Your Garden Catalog?

January 6, 2012

Late December and January begin the annual flight of vegetable, flower and fruit tree catalogs to your mailbox. Depending on your level of gardening, the catalogs arrive frequently and in mass.

It used to be you get a vegetable catalog or a fruit catalog or flower catalog. Many catalogs now contain something for everyone, including the garden gadget addicts. There are catalogs offering heirloom vegetables, flowers, and fruit trees. These heirloom varieties can be some of the best tasting and or more unusual looking fruits and vegetables we get to eat. They are called heirloom since they have had no or very little traditional breeding. This can mean you will have more disease problems with them too though.

With all the breeding work going on, our vegetables can take on new colors that are a bit outside the lines. Consider a blue potato or perhaps the more acceptable colors of green peppers, yellow, red, purple, orange and even multicolored. These look great in salads and other dishes, giving a bright look to whatever you are preparing. It used to be that Swiss chard was green, now in shades of pink, orange, yellow, gold, white and purple. Newer varieties have a much more slender stalk and can be used to brighten up salads or cooked as you would use spinach. Even our small fruits like strawberries come in a variety of shades of red now. Small fruits can be other plants besides strawberries and raspberries now. Plant breeders have had good success transforming the smaller fruiting shrubs too like currants, gooseberries and aronia into very well performing plants for the home garden. You will find heirloom and new cultivars of our perennial vegetables. Rhubarb and Asparagus are great additions to the garden.

Now go looking for the gardening gadgets. If you start your own seeds, gardeners will find a source of pots, seed starting soil mixes, markers, and more. You get to start your seeds in flat, individual cell packs like you see when you buy your annual flowers, or even expanding pellets. Pots can be out of plastic or an organic fiber. Some of the accessories that make starting your own seeds easier include warming mats in sizes from one six pack to a full tray. Other items you will find include plant stands with growing lights and self watering trays. You will also be able to pick from a variety of temporary structures for outdoor use to grow out and harden your vegetable plants before they go into the garden. There is always hand tools galore offered. Some will be perhaps more useful and used more often than others, so choose wisely.

If your mail box is not quite full enough, go to the internet and sign up to get a few more It is quick and easy or just wait a bit till each catalog sells their mailing list and then watch out!