Spring is just around the corner, and many gardeners can't wait to start planting vegetables. How early you can plant depends on the last freeze date for your area and the cold hardiness of the vegetable. For southern Illinois gardeners, the time to plant the early-season vegetables is fast approaching.

Vegetables are usually classified into two groups to help distinguish when they can be safely planted.

The first group is the cool season crops, which includes the very hardy and frost-tolerant vegetables. Very hardy vegetables withstand freezing temperatures and hard frost without injury, making them the first to be planted in the garden. As soon as the ground can be worked, these vegetables can be planted four to six weeks before the average frost-free date, which is around April 15 to May 1 in Southern Illinois. Examples include leaf lettuce, spinach, and turnip.

The frost-tolerant (semi-hardy) vegetables are planted next. These vegetables can withstand light frost and can be planted two to three weeks before the average frost-free date in the area. Examples include carrot, chard, and radish.

The second group is the warm-season vegetables, which includes the tender and warm-loving vegetables. Tender vegetables need to be planted after the frost-free date in the area. They can be injured or killed when exposed to freezing temperatures, and their seeds do not germinate well in cool soil temperatures. Tender vegetables can also show signs of injury with cool temperatures.

Tomatoes, for example, will show signs of chilling injury with temperatures between 32 and 54 degrees. The warm-loving vegetables, like sweet potato, pumpkin and watermelon, are even less tolerant of cool temperatures. These crops require warm soil temperatures for good growth and development and are the most tolerant of high summer temperatures.

One potentially difficult challenge for a gardener is dealing with a shady area. As a reference point, the definition of "partial shade" is that the plant receives no more than a few hours of dappled shade with no direct sunlight. "Shade" means the complete absence of direct sunlight.

One obvious choice for shade areas is Hosta (Hosta spp.). They come in a variety of colors and sizes. However, there are other species that can also be used.

As you get questions from clients, offer these suggestions for a perennial shade garden.

Common Bugle Weed (Ajuga reptans) is a tough European plant that grows 3 to 6 inches in height with an indefinite spread. In other words, it can be aggressive. Do not plant it next to a lawn, unless you want it to mix with the grass. Flowers are typically violet blue and occur in late spring. Some cultivars have foliage that is variegated with bronze-red to reddish-pink-white markings. The less sun it receives, the more green the leaves will be. Common bugle weed prefers moist soils but manages in dry locations. It really prefers full sun but does quite well in partial to full shade.

Astilbe (Astilbe x arendsii), from the Orient, is a mainstay for shade gardens. Flowers occur in late spring to mid-summer. Colors come in tones of pink, lavender, red, and white. Depending upon the cultivar, the mature height may range from 1 to 4 feet with a spread of 1 to 2 feet. It prefers moist soil and partial to full shade for best growth.

Goat's beard (Aruncus dioicus) has creamy white flowers that visually pop in the shade. They are born in late spring and last until early summer. Goat's beard is a native plant that prefers full shade in the lower Midwest. It resembles astilbe. However, it is much larger and may be mistaken for a shrub. It grows 4 to 6 feet in height with a spread of 2 to 4 feet. Goat's beard requires consistently moist soil conditions.

Bleeding heart (Dicentra exima) is a native plant with bluish-green foliage that somewhat resembles a fern. It has heart-shaped flowers that are pink to purplish-red. The inner petals protrude and give the appearance of a drop of blood at the bottom of each flower, thus the common name. The blooms occur in summer, and under ideal conditions, can continue until fall. The plant grows 12 to 18 inches in height with a similar spread. It requires partial shade and consistently moist soils that are not overly wet. Be aware that Japanese bleeding heart (Dicentra spectabilis), which is not native, is a related species that goes dormant in the summer.

Barrenwort (Epimedium spp.) is a genus of plants that are native to Europe and Asia. The flowers are small and occur in mid-spring. Depending upon the species or cultivar, they are typically white, pink, or red. Mature height will vary from 6 to 16 inches with a similar spread. Barrenwort prefers partial to full shade and evenly moist soil. However, it will tolerate dry sites. Some species' leaves attain red fall color.

Virginia bluebells (Mertensia virginica) are true harbingers of spring. Buds and the emerging funnel-shaped flowers are pink before turning bluish-lavender early in the season. The one disappointment is that by mid-summer, the foliage has turned yellow and died as the plant goes dormant. Plant this native among other plants that require the same conditions. It grows 12 to 18 inches in height with a spread of 12 inches. Virginia bluebells require moist, well-drained soils and partial to full shade.

Bethlehem sage (Pulmonaria saccharata) has fuzzy foliage that has attractive white or silver spots, depending upon the cultivar. In early spring, this European native has pink flower buds that open into pink flowers before turning blue. The plant's mature height is 12 to 18 inches with a similar spread. Bethlehem sage requires partial to full shade and well-drained soils that are rich in organic matter.

As you work with clients in your county, help them explore the possibilities of a shade garden. Granted, the number of plants that can be grown in a shady area is fewer than in a sunny area. But with careful selection and a little planning, a shade garden can rival a sunny border.

Every year, Extension offices get questions from clients about pond weeds, and algae is one of those weeds people ask about a lot. Spring is the ideal time to control algae, that greenish, slimy stuff that becomes problematic for pond owners. The key to effective control is to start early in the year, preferably in early April, while the water is cool and the algae is growing slowly.

The safest herbicides are copper-containing products like copper sulfate or copper chelates. Applied in April, these products provide good control with little danger to the fish, and there are few restrictions on using the pond. The water can still be used for drinking, fishing, and swimming. Just remind clients to carefully read and follow all label directions on the herbicide.

Another product that can be used is a dye. The product is known by various labels but is normally a dark blue solution. When the dye is added to the pond, it changes the color of the water to a bright blue. This process does two things–it reduces the light penetrating the water, and it reduces the plants' ability to grow. The result is less algae and submerged plant growth.

Pond owners need to use the dye product in April before the water temperature gets above 60 degrees. The warmer the temperature, the faster the plant kill. If weed control is done later in the season with warmer temperatures and more weeds, the decomposing weeds in the pond may remove too much oxygen from the water, causing a fish kill if aeration isn't provided. That's why it is important to start early in the season while there are few weeds and the water is cool.

Be sure to explain to clients that is not necessary to control all the weeds in a pond. Some vegetation in a pond is beneficial because it provides cover for the young fish, adds oxygen to the water, and is a food source for fish and other organisms that fish will eat. But when there is too much vegetation, it can interfere with other uses of the pond.

The goal is to keep weeds under control but still leave some vegetation for the fish. Advise clients to properly identify the problem and then select an appropriate control measure.

Are your ornamental grasses flopping over? Is the center of the plant dying? Or, has one of your grasses outgrown its space?

These are signs that ornamental grasses need to be rejuvenated. Dividing is a method of re-establishing a smaller grass clump that will stand. Dividing grasses is also an opportunity to relocate or transplant them in the garden. The best time to divide an ornamental grass is during the spring, just before or at the onset of growth.

Dividing is an easy process. Start by digging up the grass clump. In some situations, these clumps may be quite large. Next, take a spade and divide the clump in half. Larger clumps can be divided into several smaller clumps. Then, replant these clumps at the same depth they were dug.

The ideal time to seed a lawn in southern Illinois is in the late fall. But if you decide to establish a lawn in the spring, March is normally the best month.

The greatest threat to a spring- seeded lawn is the increased weed competition, so a good weed control program is important for success.

Be sure to read the product label on any pre-emergent herbicide that is used on a newly-seeded lawn. Most products have restrictions on how soon after grass emergence they can be applied.

Tupersan (Siduron) is the only pre-emergent control for annual grasses that can be applied to a newly-seeded lawn. Once the grass plants in the lawn are well established, any pre-emergence herbicide will work.

Broadleaf weed control should not be applied until the lawn has been mowed at least three times. Fertilizer can be applied when the new seedlings have reached a height of 2 inches. Apply ½ pound of nitrogen per 1,000 square feet of lawn area. Then, thoroughly water the lawn after fertilizing.

A newly-seeded lawn should be mowed when the foliage has grown about 50 percent higher than the desired grass height.

The height that a lawn is mowed affects the rate of weed invasion and the lawn's ability to recover from insects, diseases, and stress such as drought. The higher the lawn is cut, the deeper the root system develops in the plants. The recommended cutting height for cool-season grasses like tall fescue or bluegrass is between 2 and 3 inches.