Fall Gardening Tips for Zone 4

Fall Gardening Tips for September Through November:

Below are fall gardening tips for gardeners in zone 4. Your timing may be different depending on your location. These same tips have been featured in a recent newsletter. To sign up for our newsletter please visit our website and enter your email.

Fall is a great time to plant hostas!

Hosta roots continue to grow until the ground is frozen. We have planted Starter TC hostas as late as the second week of November in Minnesota while it was snowing, and they did great.

The one exception might be with fragrant hosta varieties that evolved further south in eastern China from H. plantaginea. However, these fragrant varieties are often hybridized with more cold tolerant hostas so it is difficult to predict. To over winter well, they might need to get more established before planting or make sure you cover them through the winter.

Hostas planted now will come up looking fresh in the spring. A cold winter dormancy triggers plant hormones, called vernalization, that make the plant better.

Do not fertilize after July 31st. Your plants need to slow down so they can go dormant.

We recommend you label your plants before winter with a durable plant identification marker. The styrene labels that come with our plants or from other vendors get brittle, break, or come out of the ground easily.

From our experience and those of our customers, it is very frustrating to not be able to remember your plants’ names. Our IDeal Garden Markers business offers unique stake and nameplate options, custom engraving, and labeling services and products.

fall gardening tips

Water your plants in the fall.  Dry conditions during this period before dormancy leave the hostas subject to crown rot. In addition, oxygen in the root area creates healthier plants. Remember that hostas planted under trees may need extra water as the tree’s foliage may prevent the water from getting to the hostas, and their roots compete with hostas for what moisture there is.

Slugs: You will get “most bang for your buck” by putting down slug killer just before the slugs lay their last batch of eggs. In Minnesota that is often around the second week of October. For more information on slugs and other hosta pests, see our Hosta Pests Info page.

Foliar Nematodes:  These microscopic worms that leave brown streaks in your hosta’s leaves start to appear as early as late June in the south and the third week of August to the third week of September in the north. HostasDirect, Inc. has never had a foliar nematode reported in the plants we have sold in 9 years. More information on Foliar Nematodes here!

With our Starter TC and Advanced Starter, you are assured of a clean plant as they are grown in sterile clean room environments and virus tested.

Our Mature Divisions were all started from Starter TC – and we have never had one complaint.

Removing blooms or seeds: To help the bees and other pollinators, we recommend you please leave your blooms on your plants until the blooms expire. Then, you can cut off the blooms before they go to seed. Removing spent flowers before seed production will allow more energy to go into the plant.

Should you cut off your hosta’s foliage before winter? Doing so saves a lot of work in the spring. In addition, some gardeners think cutting off and removing foliage creates less of a haven for foliar nematodes, fungal diseases and slugs, and your yard looks clean in the spring.

Fall Gardening Tips for November or December:

Do NOT use wood chips for winter cover! Wood chips may cause your plants and their roots to rot.

For HostasDirect’s recommended winter mulch method, see our Overwintering Perennials Page.

Cover some perennials just after the ground freezes!  Covering is cheap insurance to protect your investment of time, money, work and emotion. We recommend covering all first year perennials you purchase from us. In particular mini and smaller hostas (as they have more shallow roots), hostas and coral bells planted later in the season, and fragrant varieties of hostas. Beware of voles and mice.

How and what to use for covering plants: In the first year, after the ground is frozen, protect your hostas and coral bells with 6” to 1’ of straw or leaves (in a bag or secured by other means so they don’t blow away). This helps stabilize soil temperature and moisture ranges, reduces freeze / thaw, and prevents hostas from growing too early in the spring only to be damaged by frost or snow.  See an illustration of this method here.

The benefit of snow: Snow acts as insulation and keeps the soil temperature warmer and more even. We worry when there is little or no snow and the temperatures are very cold and prolonged!

If you follow the above fall gardening tips, your plants should come up looking fresh in the spring. Please note that these tips are for Zone 4. Your timing could differ based on where you are located.

Organic Disease Control

Fungal OnionAvoid dangerous fungicides with these simple steps to prevent disease and protect the health of your garden.

Know the Basics

Fungi, bacteria and viruses cause disease by living within host plants or devouring them, and each of these organisms causes distinctive symptoms to develop in your plants. The symptoms exhibited by your plants will be the key in determining what disease you are dealing with.

FungiGall 01

Some species of fungi live only on dead organic matter, such as many of the fungal species responsible for decomposition, while others prefer live plants.  Some are capable of attacking both living and dead tissue, choosing live plants during the growing season and surviving quite well on dead material to overwinter. Their method is to release toxins that kill plant cells, thus weakening the plant and enabling the attack. Fungi propagate by releasing air-borne spores that can germinate immediately, or lie dormant for years waiting for the right conditions to develop.

Fungi are responsible for more plant diseases than bacteria or viruses. The damage can appear at the base of stems, the crown of plants, or within the foliage, flowers or fruit. Symptoms include rotting tissue, mold, spots, wilting, and leaves with blisters or curling. Smut is a sooty mass on grains and grasses. Galls are a form of swelling or abnormal growths. Powdery blisters on leaves that are either reddish brown or yellowish are known as rust.

Fungi are dependent on moisture and thus good soil drainage is one method of controlling them. Improve soil drainage by adding organic matter or planting in raised garden beds. Air circulation also prevents moisture from building up on flowers, fruits and foliage, so space plants so that air can circulate between them.  Avoid gardening under wet conditions to prevent the spread of spores. When watering your plants, avoiding wetting the leaves, and water early in the day so that your plants have time to dry during the day. Prevent damage to your plants, as damaged tissue is easier for fungi to attack. Remove all diseased parts of a plant as soon as you notice symptoms and only compost that material in a hot compost pile where temperatures exceed 160 degrees or dispose of it in sealed plastic bags or by burning.

Bacteria InfectionBacteria

Bacteria are microorganisms that cause a variety of blights in stems or rotting in leaves, stems, crowns or fruit, characterized by slimy and smelly tissue. Bacterial infections can result in the release of a foul order, which helps distinguish them from a fungal disease.

Bacteria can survive the winter in decomposing plant material, in hibernating insects, in galls on living plants, and in your garden soil. They can survive for years within a host but unlike fungi, do not have extended periods of dormancy.

Healthy plant tissue is an effective barrier to bacteria but any bruising or damage will enable bacteria to circumvent such defenses.

Remove damage sections of plants immediately upon noticing symptoms of disease. Burn or dispose of this material in the trash, if your compost does not exceed 160 degrees.


The symptoms of viral diseases are similar to those of nutrient deficiencies, such as stunted or abnormal growth, mottling, streaks, or spots.

Viruses are most often transmitted by an insect host such as aphids or leafhoppers, or other sucking or chewing insects.

Hot compost is ineffective in killing viruses, so once you have removed diseased material from your garden, burn or dispose them in sealed containers with your household trash.

Cultural Controls

The first step is to choose cultivars that are resistant or at least tolerant of disease. They often accomplish this by differences in their biological chemistry or by structural difference such as thicker tissue or leaf pores that open at a time of day not beneficial for the disease.

Healthy soil is a critical component of your garden’s defense against disease. Plants grown in healthy soil have balanced nutrition and proper moisture and aeration, and are thus more vigorous and better able to defend themselves against disease.

Watering frequently increases humidity around plants and creates ideal conditions for rot. Water early in the day, so that the surface of leaves can dry before nightfall, and water less frequently but more deeply so that water percolates deep into the soil.

Clean your garden annually, in the autumn, to reduce pest, weed and disease issues as this will minimize the opportunity for organisms to overwinter successfully in your garden. Clean your gardening tools regularly to prevent the spread of disease.

Physical Controls

Once you have identified the symptoms of a disease, remove the disease organisms from your garden.  Remove leaves, stems, fruits or flowers that show signs of disease. If the root or crown is rotting, dig up the entire plant, including the roots and nearby soil, and dispose of them in sealed containers.

Mulch not only protects against weeds, it also prevents some fungal spores from spreading through splashing rainwater.

Trellises and staking promote air circulation, as does pruning, but do so carefully. Sterilize your tools between each cut with a 10% bleach solution, and prune back to a healthy bud or main limb, as a bare stub of woody material will simply be another entry point for disease organisms and pests.

Chemical Controls

In an organic garden, chemical controls involve the use of growth-enhancing sprays or natural fungicides and bactericides.

Growth enhancing sprays contain nutrients and hormones that encourage vigorous growth, enabling your plants to more successfully fight of disease. You can make a natural spray at home from stinging nettle.

Gather one pound of stinging nettles. Crush them and put them in a cloth sack or pillowcase. Soak the sack in one gallon of unchlorinated water in a covered bucket in a warm place. After one week, carefully open the bucket, as the odor will be strong. Strain through a cheesecloth and store in glass jars for no more than one month. Spray your plants to repel aphids and administer a dose of trace nutrients.

A .5% solution of baking soda helps to protect against fungal diseases, especially in roses. Dissolve one teaspoon of baking soda in one quart of water. Add a few drops of liquid soap and spray on infected plants, including the underside of leaves.

Sulfur has been used as a fungicide for thousands of years. Fungal spores cannot germinate in a sulfur film. Preparations of it are sold as a powder or liquid.

Our next blog will be on Insect Control.


Chemical-Free Yard & Garden: The Ultimate Authority on Successful Organic Gardening, Fern Marshall Bradley, Editor



Disinfecting Garden Tools Properly

Killing diseases on your garden tools

Garden tools and plants are expensive.   It is important you take care of both and try not to get plant materials that are infected in your garden in the first place!

One of the most, if not the most famous botanist in the world regarding shade perennials and in particular hostas is W. George Schmid.    He has authored such scholarly books as, “The Genus Hosta” and “Encyclopedia of Shade Perennials” and is a frequent contributor to “The Hosta Journal” and other scholarly works.    I asked George recently if he had seen any studies regarding how long to disinfect garden tools, which is increasingly important to prevent the spread of foliar nematodes and other garden diseases.   Here is what George wrote:

“To really disinfect your equipment, it must be very thorough. Brand new tools you can dip, but most of have those old, well used tools.  For those, use 1 part chlorine bleach to 10 part clean water solution.  It is important to wash the dirt off your equipment prior to soaking your equipment in this solution for at least 10 minutes to ensure that all microbial agents are killed.

Soaking in either a 1-to-5 solution of chlorine bleach or a full-strength Lysol or Pine-Sol brought the most consistent protection, as shown in tests conducted by UGA.  Just dipping the blade quickly often did not disinfect properly.  Chlorine bleach generally did a better job for quick dips, although none of the disinfectants proved 100% effective when using quick dips.  So soaking is recommended in all cases.  Tools have sometimes microscopic scratches that can contain air bubbles, which will prevent contact with the solution.  Soaking overnight is most effective.

Although chlorine bleach is the least expensive and generally most effective disinfectant, bleach does corrode tools when used frequently.  It also can splash up and ruin clothes. Lysol caused the least damage to clothes and tools.”

Tom Carlson, owner of this blog and of HostasDirect and IDealGardenMarker adds, “If you leave your tools in these solutions too long you will get corrosion, and possibly lots of corrosion.   So, the trick is to soak as long as needed but not much more.    Then, wash the tools with water and wipe it dry or let it air dry.   Plain water will rust tools very fast as well.