Extension Educator, Local Food Systems and Small Farms
Extension Educator, Horticulture
March 25, 2009
While 60-70 degree temperatures get us used to spring/summer, we may be jumping the gun on planting warm season garden items. Many annual flowers, tomato plants, and other warm season plants should not be set out until after May 10. When we look at our average frost free date, we see that it is April 25. About half the time in the last 30 years, the average last spring killing frost has occurred by this date. That also means that about half the time it hasn't. The last two years have been good examples of a late-season freeze occurring.
Those selling transplants love those of us that like to buy these plants in mid-April. More years than not, they get to sell us at least two sets of transplants. Of course all bets are off if you use protective covers (such as milk jugs, row covers, or wall-of-water types of protection). Usually it is just as easy to wait until the recommended date, and that would be after the range of April 25-May 10 for green beans, sweet corn, and tomatoes. These are all considered "tender vegetables."
Melons, peppers, pumpkin, and squash are considered "warm-loving" and should be planted in the range from May 10- June 1. Pumpkins planted for Halloween jack-o-lanterns should be planted about Father's Day. Pumpkins will get ripe too quickly for use in late October if planted the normal time. Pumpkins for pies can be planted in the May 10 to June 1 period.
We are getting quite a few questions about fertilizing a garden. The normal (without soil test information) rule-of-thumb rate for fertilizing flower or vegetable gardens is about 15 pounds of 10-10-10 per 1000 square foot of area. If you are using 12-12-12 or 13-13-13 fertilizer, use about 12 pounds per 1000 square foot. Soil pH may need to be adjusted due to the addition of lime and sulfur, which are acidifying. Generally, about 4.25 pounds of lime neutralizes the acidity from one pound of nitrogen or sulfur. Beware of pH requirements for different plants before you go out to apply lime. Surrounding plants are also affected. Examples would be blueberries, rhododendron, azalea, pin oaks, and many evergreens.
One of the more popular questions, at least during the growing season, concerns how to prevent the leathery rot on the bottom of tomatoes. The leathery rot is called blossom end rot. It is caused by a calcium imbalance in the plant. You could apply some lime to the area where tomatoes will be planted, because lime supplies calcium. The more reliable method is to mulch tomato plants well. This evens out the soil moisture available to the plants. The alternative is watering on a frequent basis, but too much water can cause root rot problems.
When soil conditions permit, it is time to plant things such as asparagus crowns, leaf lettuce, onions, peas, potatoes, radishes, rhubarb plants, spinach, and turnips. Give it another week or two and it is time to plant such things as broccoli, cabbage, and cauliflower. As with most things, a little bit of planning goes a long way in preventing problems later on.
· It is time to get the crabgrass preventer on, but don't apply if you seeded your lawn.
· Cut back butterfly bushes to live material, with a 10 inch maximum height.
· Cut back mums, but leave two inches of dead material since much stored food is located there.
· Cut back ornamental grasses to a height of four inches or so.
· Apply imidacloprid (Bayer Advance Tree and Shrub insect control and other names) to kill adult Japanese beetles as they feed on ornamentals. Don't use on fruits and vegetables.
March 16, 2009
Warmer temperatures have us thinking spring. Lawns will be greening up very soon, and areas protected under leaves or other types of loose mulch are already there. Spring seeding lawns is usually our second best choice, because of the warm weather soon to follow. Fall has been the preferred time for many years, but temperature and moisture have a great effect on success.
Spring seeding should be done between March 15 and April 1 for the best chance of success. The reasons for the early date are the heat and the long germination time for Kentucky bluegrass. It can take up to a month for bluegrass seed to germinate. This means an April 1 seeding might germinate May 1. Then add six to eight weeks for it to become established. This could then be close to July 1. Usually we tend to get hot weather by then. Let's start with the basics. The normal seedings are a blend of Kentucky bluegrass, perennial ryegrass, and fine fescue. The fine fescue is much better in shade, and the perennial ryegrass will provide quicker cover. The seeding rate is generally four pounds per 1000 square feet in bare dirt seedings. Use two pounds per 1000 square feet in overseeding thin lawns. Of course this can run into some real money when doing very large areas. Many rural seedings are done more on the basis of a pound per 1000 square feet. There are almost 44,000 square feet in an acre, so you can do the math on this one.
Fertilizer is always an area of many questions. The place to start is a soil test. This will tell you where you are starting from. Basic soil test levels for phosphorus, potassium, and soil pH should be in the neighborhood of 40, 350, and 6.1 respectfully. Phosphorus and potassium are on a pound per acre basis. This must be considered if you use labs that report in parts per million, which will give numbers half as large. These numbers will provide a great environment for grass. Grass will really grow in very poor conditions, but it certainly won't have that manicured lawn look many strive for. Lacking a soil test, or being at recommended fertility levels, general maintenance applications provide a pound each of nitrogen, phosphorus, and potassium per 1000 square feet of lawn area in May and again in September. Really lush lawns will usually have twice as much nitrogen applied in a season, but split among four applications. Hang on to your wallet again this year, as fertilizer prices have increased dramatically.
If you decide to try seeding this spring, remember a couple of things related to weed killers. Number one, you can't use crabgrass preventer in the same season as you put down seed. The crabgrass preventer doesn't know the difference between grass seed and weed seeds. The second rule is to mow the new seeding at least three times before trying any broadleaf weed killer. Generally this means spring broadleaf control doesn't happen when you seed in the spring. The end result is if you seed in the spring, you control weeds in the fall. Seed in the fall, and you control weeds and crabgrass in the spring. If you do plan to use a crabgrass preventer, time it so it is on about the time the forsythia blooms. This would be the approximate soil and air temperature needed for the crabgrass to germinate. April 1 is a good guess, but this date can vary widely with the weather. Many crabgrass preventers also only last for four to eight weeks, so plan on repeating the application in June anyway.
March 16, 2009
Pest Season Comes Again
With some warmer days, come some of the many nuisance pests. Over the years, we have battled many nuisance pests such as boxelder bugs, elm leaf beetles, and crickets. None of them compare to the multi-colored Asian lady beetle. These ladybugs are everywhere, and they'll find a way inside the home whenever we get warm spells.
Right now they alternated between resting and sunning. These are the beetles that overwintered as adults, and are looking for a place to stay and something to eat. The place to stay is on the side of something in the sun (in order to warm up) and the something to eat is soft bodied insects such as aphids. Without aphids present, these ladybugs will chew on about anything.
The best control in the home is a vacuum cleaner. If you have numbers too large for that control, area sprays of an aerosol flying insect killer will knock down the ones it hits. If you are terribly bothered, try a perimeter spray of the foundation, door areas, and window areas on the home with a pesticide that will last for a while. Color test the material on siding first, and hope for the best. The pesticides are effective, but they are sometimes overwhelmed by the number of ladybugs that you are trying to control. Permethrin is probably the most commonly used pesticide for perimeter sprays.
Also with some warmer weather comes the swarms of insects that raise that perennial question of "Are they ants or termites?" Swarming time for both insects is about the same time, and they are really looking to start new colonies because they have outgrown their old ones. This is the reason for the winged insects, the wings allow the ants or termites to cover larger areas to start their new colonies. The differences between ants and termites are several.
Let's start with the body color. Termites are always blackish in color, while ants may be black or other colors. If you have winged insects that are not black, you don't have termites.
Next look at the body shape. Ants have a constricted "waist" while termites don't have that classic hour-glass figure. Antennae and wings are the other two body parts to look at. Antennae on ants are elbowed, basically in an "L" shape, and those on termites are straight. Both ants and termites have pairs of wings, but those on termites will be of equal length while ants will have wings of different lengths.
There are several other items to keep track of this time of year, if you're so inclined. Following is a brief list in bulleted form:
March 10, 2009
When it comes to spray programs for apple and pear trees, the two rules are to be consistent and be persistent. Quality fruit these days takes these two things, and time. It seems like quality fruit must be sprayed at the recommended intervals. Starting with dormant oils, these need to be applied before buds swell. Dormant oils are usually needed only every two or three years to provide control of scales and mites. Sure, the populations will build up in the off years, but should remain relatively low if the three-year program is followed. Dormant oils do require temperatures above freezing for 24 hours, but you want to be ahead of the bud swell.
The first regular spray of the year is applied when the green tissue is ½ inch out of the bud. This spray for homeowners usually consists of a multipurpose fruit spray (and sulfur if needed for powdery mildew). Multipurpose fruit spray has been re-formulated the last few years to include malathion, captan, and carbaryl (methoxychlor was eliminated from the old mixture). This same mixture would be used when the fruit buds are in the pink stage (when fruit buds show color). After that, the persistence and consistence pays off as you spray with the same mixture about every 10 days until we get to within two weeks of harvest. In our area, we need to continue spraying this late because of apple maggot and sooty mold.
This spray program will also control borers on apples and pears, if you also thoroughly spray the trunk and main limbs of the trees. On non-bearing, young fruit trees where borers have attacked, you can spray the trunks every two weeks during June and July with a multipurpose fruit spray.
The spray schedule for peaches, nectarines, apricots, and plums varies a little bit. The dormant spray for them uses captan fungicide. This is the only spray that controls leaf curl and plum pockets. The next spray is when fruit buds show color with captan, followed by captan at bloom. When the husks begin to pull away from the base of the fruit we would then spray with sulfur, captan, and malathion. This mix would then be used every 10 days or so to within a week of harvest.
For borers on the peach group, you can spray or paint the trunk only with carbaryl (Sevin) on June 15, July 15, and August 15. We have some challenges with the loss of some of the insecticides, since carbaryl can cause fruit drop or thinning on the peach group and some apples.
March 10, 2009
Application of imidacloprid (Merit and other brand names) and other systemic insecticides is effective in controlling Japanese beetle adults. Although the imidacloprid occasionally doesn't work in a tree to control this pest, it does over 80 percent of the time. However, a soil application of imidacloprid typically takes 6-8 weeks to move completely up to the leaves of large trees. With Japanese beetle emergence typically starting the fourth week of June in our area, the sooner the better for application. This would be a prime option for linden trees, crabapples, rose bushes, and other favorites of the Japanese beetle.
Imidacloprid can be soil-applied either as a drench or by injection. Because imidacloprid is easily tied up on organic matter, mulch and other dead organic matter must be removed from around the base of the tree before a drench application is made. Removal of turf around the tree would also be recommended for a drench. Soil injections should be made deep enough to get below mulch, turf thatch, and other organic matter, but not deeper than 3 to 4 inches. Apply to the soil within 1 to 2 feet of the trunk, where the greatest concentration of fine feeder roots is located.
Just remember, each beetle must eat some leaf to get the insecticide. If a million beetles all take two bites of your linden leaf, there are still going to be a lot of linden leaves eaten. Don't use this treatment on fruit or small fruit trees unless labeled.
March 4, 2009
University of Illinois Extension is gathering input to help us plan programs. If you are over 18 and would like to participate, the link is in the upper right corner of the home page (Tell Us) or try the direct link
The total time of the online survey should be 10 to 15 minutes. Thanks for your help!. The total time of the online survey should be 10 to 15 minutes. Thanks for your help!
March 4, 2009
What has often been termed the Queen of the Vines, clematis, can offer rich, striking beauty as does royalty, said a University of Illinois Extension horticulture specialist.
"At the same time, it can be very temperamental just as some royalty can be," said Greg Stack. "But once you have decided to include clematis in your garden, there are a few things that should be noted so your 'royal resident' will find your garden to its liking."
Clematis are members of the buttercup family and have well over 300 species and countless man-made hybrids in the group. Not all of these are suited to Midwestern gardens and so selection needs to be done carefully.
Clematis are mainly woody, climbing plants. They do not attach themselves to supports by twining stems, aerial roots or tendrils.
"However, they attach by twining their leaf petiole around support structures," he said. "Because of this, thought has to be given to providing the proper supports otherwise they will ramble along the ground until they do find suitable support.
"The best supports are those things that are less than three-quarters of an inch in diameter. Clematis petioles find this size to be the easiest to wrap around. Many gardeners find that using heavy fishing line is a good way to get clematis to climb up poles or arbor posts."
If a knot is tied in the line at 12 inch intervals, this will help keep the vine from sliding down the fishing line, he added.
In the wild, clematis is often found growing at the edge of woodlots where they climb through the tree limbs to reach full sun while their roots remain in the shade.
Success with clematis starts with proper soil preparation, planting, and after planting, pruning.
Clematis prefers a cool, moist, well-drained soil for best growth. They do not like poorly drained soils especially those that stay wet over the winter. While it is true that clematis prefers alkaline soils, they will grow successfully in soils that are neutral (pH 7.0) to slightly alkaline (pH 7.5). To determine if liming is necessary, a soil test should be taken to guide you on how much if any lime needs to be added. Annual liming is not suggested as over-liming can lead to other nutrient deficiencies.
"When preparing the planting site, be generous with the planting hole," he said. "Dig a hole at least twice as wide as the pot the plant is in and at least twice as deep. This allows for adequate organic matter to be incorporated into the site, a key to good root development.
"When planting, plant deep. Place the crown of the plant at least two to four inches below the surface of the soil. This will help with the production of stems from dormant buds below the soil and also helps the plant recover if stems are injured by animals or mechanical means."
Newly-planted clematis should be pruned back to about 12 inches in the spring following planting. This pruning will encourage new shoots to develop and will produce a fuller, bushier vine with many more stems and a not-so-bare bottom.
Clematis like to be fed but not overfed. Fertilizing in the spring with a general purpose fertilizer right after pruning should carry the plant through the season.
"Because clematis prefers cool soils, some type of mulch should be used over the root area," Stack said. "Planting a low perennial groundcover near the plant often works well or organic mulch can be used.
"Apply about four to six inches of mulch at the base of the plant, keeping the mulch about eight inches from the stems to avoid stem rots."
Now comes the mystery for many gardeners when growing clematis: when, how and where do I prune?
Stack answered that pruning clematis is not complicated and even if done incorrectly it is not fatal. The worst that can happen is you will either delay flowering or flowering does not occur for a year.
Clematis is divided into groups or categories for pruning purposes. They are designated as A, B, C or 1, 2, 3, or hard, half pruning or none, depending on what source you are reading. In any case, always look at the tag that accompanies your plant. It will often mention the pruning category your plant falls into. Take note and there will not be any doubts.
For group A, these plants flower on "old wood" or last season's stems. For these varieties only light pruning is done in the spring to remove dead stems. Another pruning opportunity occurs right after the plant has finished blooming. Prune in late spring or very early summer. The resulting new growth now becomes next season's flowering stems.
Group B clematis flower on both old and new wood. Because of this it can make pruning a bit more challenging. Prune lightly in spring, removing dead and weak stems. The largest flowers will be produced on the old wood while new growth will provide bloom for late season. If a group B clematis ever needs major pruning to rejuvenate it, a hard cutting back can be done right after spring flowering and still have plenty of time for the new shoots to provide a fall show of blooms.
Group C is the easiest. Here you grit your teeth, grab your pruners and cut the plant down to eight to 10 inches. By doing this you will ensure a lot of vigorous shoots from the base and a nice, full plant covered with flowers. Many group C clematis are often not pruned hard enough and the result is a rather "trashy" looking vine with lots of tangled stems.
"One problem that is frequently seen with clematis is clematis wilt," he said. "This problem has been attributed to a fungus and is most damaging early in the growing season when the plants start flowering. Leaf spots and partial stem rot occurs, resulting in wilted stems.
"This can happen slow or fast. Fungicides have been used as a preventative control but once the plant is affected the only suggested control is to prune out affected stems at least 2 inches below the point of infection. Most experts agree that clematis wilt is not fatal and most will re-sprout from buds located lower down on the stem."
To get you started with clematis or to add to your current collection, here are a few suggested varieties that exhibit good performance and interesting flowers:
Anne-Louise - Violet purple flowers with contrasting red-purple stripe. Blooms May-June and August–September Group B
Arctic Queen – Fully double white with a very strong habit. Blooms May – August Group B
Crystal Fountain – Lilac blue flowers with a fountainlike center. Compact plant good for small gardens and containers. Blooms June-September Group B
Franziska-Maria – Blue-purple fully double flowers. Good for containers. Blooms on old and new wood. Blooms June-September Group B
Rosemoor - Large rose-colored flowers. Blooms on old and new wood. Blooms May-September Group B
Rouge Cardinal – Large velvet crimson flowers. Blooms June-August Group C
Polish Spirit – Rich purple. Good cut flower. Blooms July-September Group C
Tangutica – Small yellow bell-shaped flowers. Vigorous grower, attractive seed heads. Blooms July-September Group C
Duchess of Albany – Pink bell-shaped flowers with red stripe. Vigorous grower. Blooms July-October Group C
March 3, 2009
We are rapidly approaching the end of the pruning season for most fruit trees and deciduous ornamentals. There are a few rules that are recommended for pruning, and there are several other items that are up to "pruner discretion." One of the beginning items to discuss is the equipment.
Most pruning can be done with three pieces of equipment. The most used piece is a pair of bypass pruning shears. These shears will cut up to about 3/8 inch comfortably, and make sharp cuts that don't tear or crush. There are still anvil type shears available, but their use is mainly in vineyards to girdle grape vine ends. The second piece of equipment is a bypass lopper. Loppers can cut up to about 1.5 inch wood, depending on the type and size. If you have the money, a good set of compound action loppers would be a good investment. The third piece of equipment is a pruning saw. These can come in several shapes, sizes, and price ranges. For smaller limbs, a folding or straight pruning saw is a good buy. For larger limbs, a bow saw may be needed. The maneuverability and ease of use are key points when selecting a saw.
The time of year we prune various trees and shrubs is important. Most trees and shrubs that aren't flowering in nature should be pruned between December and mid-March. Flowering trees and shrubs should be done after they flower. Evergreens are best pruned in late June. With oak wilt in the area, oaks should be pruned in December to lessen sap flow, which attracts virus-carrying beetles. And, any branch that hits you in the face when you are mowing should be cut off immediately (except on those oak trees)!
Basic pruning should serve to remove poor branches, keep the plant growing aggressively, and do a little bit with shaping a plant. Poor branches mean bad angles from a trunk or main branch, dead branches, branches that rub together, or multiple leaders. As far as keeping a plant growing aggressively, remember that pruning is a rejuvenation process. Regular pruning also produces more two-year-old wood that produces fruit on fruit trees, and flowers on flowering trees and shrubs. Minor shaping and sizing are possible, but major changes probably mean a different plant should be selected.
When making a pruning cut, the key is to cut back to something. Branch tips can be cut back to a bud, and entire branches can be cut back to another branch or the main trunk. When making the cut to a branch or trunk, cut to the edge of the collar (about a 1/16 of an inch from the other branch). Cutting too close to the other branch destroys the water carrying tissue, and leaving a stub will guarantee a rotten branch stub (that will eventually rot into the main branch or trunk). Topping a tree lessens weight, and reduces size, for a short period of time. Within five years of topping, you will generally have more weight and growth than you would have had without topping. If you are making cuts on large branches, it is best to cut once about 18 inches from the main branch, then make a second cut to leave the 1/16 inch collar. This will help prevent the cut branch from tearing other branches.
Hopefully these basic pruning hints will help you get started on the right foot. Remember the golden rule of pruning "If you think you've cut out too much, you're probably about right."