Tag Archive | Fall Gardening

Fall Lawn Fertilization

by Lisa Johnson, horticulture educator for Dane County UW-Extension

Man_applying_fertilizerFall is the most important time to fertilize your lawn. If you only do it once a year, do it now! Research, based on the growth cycle of turfgrass, shows that Labor Day is the best time to fertilize. Memorial Day is the second-best. Fertilizer is most effective when the highest amounts of root and shoot biomass are present to absorb and use it. Nitrogen, phosphorus and potassium are the macronutrients that lawns need most. Test your soil before applying fertilizer blends so you know whether fertilizer is needed and what type to buy.

Apply no more than 1 pound of nitrogen per 1,000 square feet per feeding, and a maximum of 4 pounds per year. Nitrogen is usually the limiting factor in turf growth, because it doesn’t accumulate in soils as phosphorus and potassium do. Lawn maintenance fertilizers with 25 to 50 percent of the nitrogen content in a slow-release, or water-insoluble form are best. They release nitrogen slowly rather than all at once, minimizing nitrogen loss due to leaching. Leaving grass clippings on the lawn and applying 1/4 of compost reduces nitrogen fertilizer needs, too.

There is a statewide ban on phosphorus in turf fertilizers, with an exception for some organic products in some counties of Wisconsin. Phosphorus, which helps build strong roots, may be recommended in soil tests if you are starting a new lawn from seed or maintaining a lawn in low-phosphorus soils. If testing recommends application, bring your soil test results to the store in order to purchase turf fertilizers containing phosphorus. In south-central and southeastern Wisconsin, we often have high to excessive amounts of phosphorus in our soils (especially in urban soils), so more is not recommended. However, this isn’t the case statewide.

Potassium helps turf increase its disease and drought resistance and prepare for winter dormancy. Potassium is present in higher amounts in winterizer turf fertilizers, but this doesn’t mean you can only apply it in fall. In many areas of Wisconsin, we have high potassium levels in soils, so it may not be needed.




Plant now for a long Tulip season

Tulip lovers stretch the season by planting lots of different species and cultivars. Though each only blooms for a short time, the tulip parade can last two full months if you plan it carefully.

Tulipa fosteriana 'Purissima'

Tulipa fosteriana ‘Purissima’

Early: The first tulips are low to the ground, including the wide-leafed Kaufmannianas, sometimes called water-lily tulips because of the shape of the flowers, and Gregii’s, known for their mottled leaves. Soon after them come Emperor, aka Fosteriana, tulips, the earliest of the long-stemmed types; Single Early, which is usually slightly taller than Emporor; and Double Early, ditto.

Mid Season: Once the days lengthen and weather warms up, you’ll get Triumphs, first of the truly long-stemmed florist’s types, which come in a wider range of colors than the early birds. Also Peony-flowered tulips, known for their lush doubleness; and Giant Darwin, the florist’s tulip on steroids.

Viridiflora tulipan (Viridiflora tulip)

Viridiflora tulipan (Viridiflora tulip)

Late: This is the season for Darwin tulips, also known as Single Late, the classic tall-stemmed cups of color that first come to mind when you hear the word tulip. It’s also the time for exotica: huge Parrot tulips, with their twisted and ruffled petals; urn-shaped Lily-flowered tulips; Viridifloras, with flames of green rising up the outside of the brightly colored flowers; and Fringed tulips, sometimes listed as Tulipa crispa, their petal edges frilled with narrow teeth that glow when the light shines through.

Species: There are dozens of species tulips available, primarily through mail order. Smaller and more delicate than garden tulips, they are mostly mid-season bloomers, with a few earlies, such as the tiny white T. biflora, and a few members of the late show, such as the bright red T. wilsoniana (T. montana). The available array keeps growing, so it is best to buy from a purveyor who is clear about blooming time in the catalog.

Storing Tender Bulbs/Corms

By Kathy McCarthy

Do you love plants that have tender bulbs but think it is too much trouble to store them over winter? Hang on folks. The results may be worth your efforts and this is a great way to increase your supply. The directions are for plants I have been successful in storing.

Remember to dig carefully. It is important to loosen the roots gently, digging a few inches away from the plant. You want to avoid cutting or breaking the fleshy structure. Diseases enter through cuts and bruises.


A gladiolus ““bulb”” is really a corm, a swollen underground stem. A new corm forms on top of the old one. While this is taking place, small new cormels are produced from the base. Corms can be dug when the foliage begins to yellow or before a hard freeze. After carefully digging the corms, cut off the old leaves close to the corm. Leave the corms outside in the sun for a day or two and then spread out in a garage or similar place to cure, but not on a cement floor. This will prevent storage rot. After a few weeks of drying, clean them by removing the roots and outer sheath of corm. Remove and discard the old corm. Store the corms in a mesh bag and hang them out of the way in a cool well-ventilated area. I use a mesh onion bag and hang it in my basement. The small cormels can also be saved and planted the following year, but it will take a few years to produce blooming plants.


Dig the rhizomes in fall before the first frost. Remove the old stalks and gently brush off soil. They can be washed with a garden hose. Let them dry for a few days before storing. I store my rhizomes in a box filled with vermiculite. However they can also be stored in peat moss. Another way to store cannas is to leave the soil on the rhizomes and pile the clumps in a box. Cover with plastic and store in the basement or other dark, cool, dry area. I put the box on top of another container to keep it off the cement floor. Rhizomes must not freeze during storage. The temperature should be between 50 and 60 degrees. Never store canna rhizomes in a mesh bag, as this will allow the bulbs to dry out.

Calla Lily

Bulbs should be lifted out of the soil in late fall, but before the first frost. The bulbs bruise, so handle them carefully. Remove the excess soil by either washing or carefully rubbing it off. Dry the bulbs away from direct sunlight or wind for several days. Put them in a paper bag and store them in your basement or other dark, dry location. Like cannas, the temperature should be between 50 and 60 degrees.

Label and Check

When storing, I label the containers carefully. You can use a permanent felt marking pen to write directly on the fleshy root. I find it helpful to attach a sheet of information regarding planting time, depth, etc. to the container.

During the storage season, I periodically check for damaged or rotting material. Any damaged material is removed and thrown away. You don’’t want one bad ““apple”” to spoil the whole bunch.

Once spring arrives, you will be glad you saved those tender bulbs. If you have more corms, rhizomes and bulbs than you can use, think of your fellow gardeners and give them away.

Save your Heirloom Tomato Seeds

'Mr Stripey' heirloom variety tomato

‘Mr Stripey’ heirloom variety tomato

I like to try different kinds of tomatoes each year and, while the hybrids produce really good and generally disease-free fruit, there’s nothing like biting into a tomato that reminds you of your childhood. That happened to me this summer with one that I hadn’t tried before — ‘Mr. Stripey’. Now, we didn’t grow ‘Mr. Stripey’ when I was a kid (not to my recollection anyway), but it has that full, just-from-the-garden sweetness that I remember. As a result, I thought I might try seed saving this year — something I’ve never done. For help, I’m taking the advice to Diana Alfuth, horticulture educator for Pierce & St. Croix County UW-Extension.

Seed Saving

by Diana Alfuth

Saving vegetable seeds from year to year can be fun and economical. Self-pollinating plants, such as beans, peas, tomatoes and peppers, are the best vegetables to save. Vine crops, including squash, pumpkins, melons and cucumbers, are often cross-pollinated by insects, so seeds saved from these crops will likely grow into plants that produce fruit unlike that of the parent plant — often odd shaped or poor tasting.

For tomatoes, scoop the seeds and gel from the middle and put them in a jar of water. Stir the mixture daily and after four to five days, the gel will break down and the seeds will fall to the bottom. Pour off the liquid, collect the seeds, and place them in an even layer to dry. Coffee filters work really well for this purpose since they absorb moisture and you can write the variety name directly on the filter. For peppers, remove the seeds from ripe fruit after they begin to shrivel and put them directly into a filter for drying. Beans and peas can be left on the plants until dry and rattling in the pods, and then shelled for storage.

Once fully dry, store the seeds in a cool, dry place, ideally at 32º to 41ºF. Put your seeds in individual paper envelopes, and then put them all in a glass jar in your refrigerator or other cool place until planting time next year. Be sure to mark the envelopes with the date and variety.

Allergies of Autumn


Beautiful stems of Goldenrod – mistakenly blamed for Fall allergies

Poor Goldenrod (state flower of Kentucky) — blamed for the itchy, watery eyes suffered by so many this time of year (including me!). It’s a shame that goldenrod is blamed for the sneezes and wheezes of autumn allergies, so I am, once again, writing an article in defense of this beautiful garden plant!

The reason, I’m sure, that so many people think of goldenrod as their autumn nemesis is because it produces those brilliant yellow flowers just when ragweed also blooms. But no one notices the culprit’s small homely pale green blooms. Goldenrod’s pollen is heavy and is moved about only by bees, whereas ragweed pollen is tiny and light and meant to be spread by the wind.

There are some 15 species of common ragweed, whose botanical name is Ambrosia (an ironic misnomer for sure). Ragweeds grow naturally from coast to coast, adapting to both country meadows and gritty city environments. The plant has fernlike leaves similar to those of wormwood (Artemisia), and is actually a tasty treat for pigs and cattle.

Ragweed is also an excellent soil preserver and conditioner, one of the group, sometimes called pioneer plants, that spring up rapidly after floods, fires, or bulldozers have ravaged the earth. So, a very useful plant for both the Earth, and for the pharmaceutical companies that collect lots of my dollars every fall as I struggle to breathe without crying!

Fall Blooming Asters

by Dr. Leonard Perry, Horticulture Professor, University of Vermont


Aster amellus ‘Violet Queen’

There are many reasons to use fall-blooming asters in landscapes. There is much variety in this large group of hardy perennials, coming in various heights and showy flower colors. You’ll find selections in all shades of red, pink, purple, white, and even blue. They’re easy to grow, most are native, and they’re one of the main plants for bees, butterflies and other pollinators in the fall. They combine well with ornamental grasses, rudbeckia, and coneflowers. With so many to choose from, how does one begin? In addition to favorite colors, look for ones that best fit your growing conditions, desired habits, and disease resistance.

The starburst appearance of the flowers leads to the name “aster”, from the Greek word for star. Asters give their name to the large composite family—Asteraceae—that of sunflowers, dahlias, daisies, zinnias, and similar flowers. The asters all used to be grouped together into one “genus” (Aster), but thanks to recent botanical research they’ve been regrouped with names more suited to botanists than gardeners. So for instance, although the New England aster genus is now changed (Symphyotrichum), the species name has remained the same (novae-angliae).

Generally, most asters prefer moist, well-drained soil and full sun. There is a range of species, however, that can be grouped by their native environments and corresponding garden preferences. The first group prefers rich, moist soil in full sun. These include the species native to meadows, prairies and marshes such as the New York (S. novi-belgii), New England (S. novae-angliae), and flat-topped (D. umbellata) asters. They prefer steady moisture. Ones that prefer moist soil, but can tolerate dry sites, include the sky- blue (S. oolentangiense), heath (S. ericoides), calico (S. lateriflorum), aromatic (S. oblongifolium), and silky (S. sericeum) asters. Tatarian aster (A. tataricus) in this group, a Siberian native, is quite adaptable to various soils.

The second group of asters also prefer full sun, along with cool nights, and very well-drained soil. This is because they are native to seashores and mountains where soil drainage is excellent. They may be short-lived over only a few years,particularly if conditions aren’t just right. In this group you’ll find the European Michaelmas daisy native to Asia Minor (A. amellus)—a name often given to many asters as they bloom around this Christian  holiday of September 29. Others in this group are the Frikart’s (A. xfrikartii) aster, of garden origin, and East Indies (A. tongolensis) aster native to western China and India.

The third group of native aster species tolerate shade (under 4 hours direct sun per day), but bloom better in part shade (4-8 hours of direct sun). The blue wood aster (S. cordifolium), Drummond’s aster (S. drummondii), white wood aster (E. divaricata), and big leaf aster (A. macrophyllus) are in this group. Although they prefer moist soils rich in organic matter, they will tolerate some drought.

In perennial trials at the Chicago Botanic Gardens (www. chicagobotanic.org/downloads/ planteval_notes/no36_asters. pdf), 119 asters were evaluated over six years. They were rated based on flowering, health, habit, and hardiness. In this USDA zone 5 site (-10 to -20F average winter minimum), seven asters stood out with five-star ratings. These top asters included ‘Jin Dai’ tatarian aster, white wood aster and its cultivar (cultivated variety) ‘Eastern Star’, ‘Snow Flurry’ heath aster, calico aster and its cultivar ‘Lady in Black’, and ‘Raydon’s Favorite’ aromatic aster. For a rock garden or low wall, where cascading stems are desired, ‘Snow Flurry’ would be a good choice. For perennial gardens and naturalistic landscape masses, good choices would include asters with bushy habits—‘Jin Dai’, ‘Lady in Black’, or ‘Raydon’s Favorite’.

In addition, there were 19 asters that rated good, with four stars. These good asters included a couple of New England asters— the rosy pink ‘Harrington’s Pink’

and deep pink ‘Honeysong Pink’, and three New York asters—the light lavender ‘Blaubox’, lavender- blue ‘Climax’, and purple-pink ‘Rosenwichtel’. Most selections you may find of the asters are in the New York and New England species. Perhaps the reasons that more didn’t rate more highly relate to habit and potential problems. Aromatic asters tend to be less problem-prone, and good alternative choices.

New England asters can get to four to five feet tall and fall over under some conditions, particularly low light. Cutting them back in early summer by one third to one half will make them more bushy, with no need to stake.


Aster ‘Purple Dome’

One of the more recent introductions of New England asters, and one of the most popular asters, ‘Purple Dome’ came from the Mt. Cuba Center and gardens in Delaware. It is violet-purple and low, only growing to about 16 inches high and about 2 feet wide. This makes it a good choice for fronts of borders, along walks, massed, or even containers. It bloomed over two months in Chicago, from early September to early November. ‘Vibrant Dome’ is a bright pink sport of this compact cultivar, not in these trials but popular and available.

‘Purple Dome’ is a good example of how resistance to diseases can vary by site. Often considered to have excellent resistance to powdery mildew, in the Chicago trials this cultivar was only rated as fair.

Asters may get rust or powdery mildew diseases on leaves. The former was seen more on the New York asters in the Chicago trials, while the latter disease was seen more on the New England asters. Giving good air circulation around plants, and disposing of leaves in the fall (not in the compost bin) will help lessen these. There are several sprays, organic and synthetic, that can be used for these too. A main destructive insect of asters may be the lacebug, a small grayish insect that appears in midsummer and sucks the plant juices from the undersides of leaves, primarily of the New York and related types. Leaves turn yellowish and eventually brown and fall off. Organic or synthetic insect sprays can be used for control. Read and follow all label directions for best control, and safety for you and the environment.

Deer and rabbits can be quite fond of asters, too. There are repellent sprays for these. Low fencing for rabbits, and deer netting for these may be needed if repellents don’t work. Several asters have been bred as alternatives to fall garden mums, including the lavender ‘Ariel’, violet ‘Celeste’, and the purple ‘Pixie Dark’. Results from the Chicago trials show these only live a year or two, so should be grown as annual flowers. Since the New York asters have problems, and are short-lived, they are not recommended either, even though commonly found.

Keeping asters healthy during the growing season—in part, growing them under the right conditions—will go a long way toward helping them survive the subsequent winter.


When to Plant Trees

tree-planting-guide-diagramFor most trees, fall is the best time to plant. The soil is warm but not waterlogged the way it can be in spring, and trees without leaves make fewer demands on their roots to provide nutrients.

A few trees, however, including magnolia, birch, hawthorn, black gum, tulip tree, and most oaks, get downright cranky when planted in the fall. No one knows for sure, but researchers think that there is something that prevents the root structure from taking up enough water to overcome transplant shock, and that winter comes before the tree is ready for it.

Studies by Dr. Nina Bassuk at the Cornell University Urban Horticulture Institute in Ithaca, New York, show that transplanting these trees when they are smaller increases the success rate for fall planting. She has had much better results with trees that measure less than 2 inches in diameter at a point 6 inches above where the trunk emerges from the roots than she has had with larger trees. Be sure to water that new tree in well. Whether it has leaves or not, it needs water.

Watering also settles the soil and helps eliminate any air pockets. Dormant trees planted in October or early November should need only that one deep, soothing watering to last them the winter. But all that said, it is still better to plant magnolias in spring.

Like other things in life that aren’t what they used to be, burlap has changed. Whether for the better depends on your point of view. A single layer of plain old untreated burlap, now almost a thing of the past, rots away nicely and lets roots wander freely out of their soil ball. But you are just as likely to run into a plastic burlap-like material, or into burlap that has been treated with a rot-resistant chemical.

Both are popular in the horticultural industry for the same reason: they stay intact longer, through sunshine and waterings, as the tree makes its way from its growing site to you. But that perseverance presents problems for growing roots trying to find their way into new surroundings. Rot-resistant burlap takes years longer to decay than untreated does, and even untreated burlap presents a formidable boundary if wadded down in layers and left in place.

In both cases, these barriers restrict the diameter of the roots as they grow out. In some cases, the tree may even die. At that point, you can dig it up and use the original wrapping to take the dead tree to the dump.

To avoid such problems, after placing the tree in that nice extra-wide-but-no-deeper-than-the-ball hole, untie the twine around the trunk and cut away the burlap.

Note: some ideas are harder to kill than crabgrass. One of them is that when a tree is dug up to be sold, the branches should be removed to compensate for the loss of roots. The rationale is to balance root loss with the removal of an equal amount of top growth. The tree is then thought to be better balanced and better able to withstand transplant shock.

As logical as this sounds at first, it just doesn’t hold up. The human equivalent might be removing the right arm of someone who has just lost her left leg in an accident.

Transplanted trees need all the food they can produce to support the regrowth of those lost roots. The food comes from leaves doing their thing, so the more leaves, the better. The only branches that should be pruned are those that are dead, diseased, damaged, or rubbing against other branches.