Springtime for Hostas:
Some What To Dos and Do Nots
By Warren I. Pollock
From DVHS Newsletter - Winter 2002
Clean Up: It seems no matter how thoroughly garden beds are cleaned in late fall, debris collects on
them over the winter. So, a thorough clean up is needed in early spring, before the shoots emerge from
the ground. If the beds are not mulched, I suggest lightly scarfing the earth with a steel rake to loosen the
soil surface.
Also, roots often get exposed over the winter. Lightly cover them with good soil. I do not
recommend hosta crowns be buried more than one half-inch deep.
Mulching: There are as many people who swear by mulches as those who say no, not in my hosta
garden. The advantages of mulches are well known: reduce evaporative water loss from the soil, control
weeds and provide decorativeness.
There are negatives, though. There is evidence that some mulches increase slug population,
increase the risk of some diseases and create a more favorable environment for votes, a pesky rodent that
tunnels near the sod surface and eats hosta roots.
The consensus among hosta fanciers that I've contacted is the best mulch is pine needles, also
called pine straw. Decades ago it was readily available at Delaware Valley nurseries as compressed,
wire-bound bales. But, alas, the bulk and bagged hardwood and pine-bark mulch merchants now have
the market cornered.
If you have access to a supply of pine needles, consider yourself lucky, as a light top dressing
seems to diminish slug problems. Cocoa mulch also seems to help to detract slugs, but you'll have to
tolerate - or enjoy - the heady chocolate aroma.
If you're a hardwood, pine-bark mulch or wood chip advocate and there is still a fairly thick
layer of mulch an your beds, check to see if it has crusted (caked) to a dense, hard impervious-to-water
covering. Some barks and woods release a resinous residue over the winter that glues the mulch pieces
together. If this happened to your mulch, break it up into small loose particles so water can easily
penetrate through it. I use a regular garden hoe, but perhaps even better is one of those spring steel three-
tined hand tools called a 'Maine Scratcher' or "claw hoe."
Also, here is some sage advice from the new American Hosta Society booklet, The Hosta
Adventure: Regardless of the mulch chosen, do not mulch heavily. Most important, do not pile the
mulch up against the divisions (shoots) as this can invite diseases. It is best to keep the mulch two
to three inches from the petioles.
The principle disease associated with mulch in contact with hosta leaf stems is Southern stem
blight that is caused by the fungus Sclerotium rolfsii. There is a misconception that this troublesome
disease only occurs in the South. The problem can occur anywhere during hot weather (over about
85'F) and when the mulch and soil are heavily wetted. Hosta growers in Minnesota, Iowa and
Illinois-- as well as in Pennsylvania and New Jersey - have reported serious S. rolfsii disease problems.
Slugs: The wise adage is to start your slug abatement control in early spring. The best time is
just before the shoots are poking up from the ground. The next best time is when the shoots have
emerged and are leafing out.
Some growers report good success with drenching the crowns and the area around the crowns
with a 10% solution of ammonia. (One-part ammonia to nine parts water.) Use regular ammonia, not the
soapy type that's also on supermarket shelves. Keep in mind, though, that ammonia is a contact
molluscicide, that is, it must be in contact for a short time with slugs and their eggs to kill them. Also,
after a good rain the solution is no longer effective.
There are two commercial slug baits being widely used. One is Deadline© RainTough containing 4% metaldehyde in the form of dark brown, rain-resistant pellets. It comes in 3-lb., shaker-
top see-through jars. It's the only slug bait we now use in our garden. (I write "we" but actually it's Ali,
my wife, who's the slug baiter in our family.) Deadline RainTough does a good job if you are diligent in
applying it early in the spring and frequently thereafter. Follow the manufacturer's instructions.
Deadline RainTough is available in Delaware Valley nurseries, garden centers and hardware stores. Last
year in my area, northeast Delaware, it was stocked by Always the Garden on Philadelphia Pike, Old
Country Gardens at Wilson and Foulk Roads, and Action Hardware in Branmar Plaza on Silverside
Road. Also, J. Franklin Styer Nurseries on US Route1 in Concordville, Pennsylvania, just a mile or so
east of the Ramada Inn in Chadds Ford where the March DVHS meetings are held, carried it. I assume
these stores will be offering it this year.
If you cannot find Deadline RainTough in your area, you can easily order it by mail from A. M.
Leonard, 241 Fox drive, P.O. Box 816, Piqua, OH 45356. There's a toll-free phone, 800-543-8955, and
a Web site, www.amlgardener.com.
A. M. Leonard sells the 3-lb. shaker jar (item number DSSK) for $11.42. You'll have to pay a
shipping charge, though. However, if you buy two jars and add the minimum required shipping ($6.95),
the cost per jar is just a bit more than what my local hardware store and nurseries are charging. If you
purchase three jars with a $7.95 shipping cost the price per jar is what one of my neighborhood sources
is charging. And you'll probably need two, maybe three, jars for the season.
The other product is Sluggo©, white granules that contain 1% iron phosphate. It is more readily
available than Deadline RainTough; you should have no problem finding it in your local area.
I have no experience with Sluggo. Gardeners tell me it works "okay." If you've used it or will be using it
this year, please contact me as to its effectiveness. My address, etc. are in the masthead on page 1.
Fertilizing:The Hosta Adventure states: Hostas are heavy feeders and respond well to fertilizing. Some
growers use a granular formulation early in the season. Others prefer a more frequent application of
liquid fertilizer to the foliage, using a dilute solution.
I spread a granular, slow release lawn fertilizer at half the rate recommended on the bag just
before the shoots emerge, and water heavily afterward. For small hostas I apply the fertilizer within
about a one-foot circle. For larger hostas, it's from the center of the clump out to where I think the roots
have extended. This, I estimate, is about 2/3 the width of the plant's leaf-spread the previous year.
In addition, when the leaves are unfurling, I drench the foliage with a liquid fertilizer at a
concentration 1/4 to 1/3 what is recommended by the manufacturer. I use Miracle-Gro© but any of the
soluble, non-acid formulas are satisfactory Afterward, I water the ground - not leaves - thoroughly.
Then I apply a second application of this foliar fertilizer just after the leaves have reached their
full size, and again water the soil well. This helps promote a second and often third flush of leaves.
Weed Prevention: I am pleased with the prevention of weed germination using Greenview© Preen©, a product of Lebanon Seaboard Corp. in Lebanon, Pennsylvania, widely available in the
Delaware Valley. The yellow granules are easy to apply from the shaker top jar.
For best results, the rate of application must be as shown on the carton, no less. In fact I suggest
applying a bit more to the soil. Furthermore, the application must be in early spring. Water afterward.
Keep granules off the leaves if they have unfurled.
A few weeds do come up, probably those already rooted before Preen was applied. But they can
be easily pulled out or killed with a herbicide (see below).
The key to success with Preen is to reapply it whenever the soil surface has been disturbed. This
prevents germination of new weed seeds that have become exposed.
I need to mention that you may not find the soil peppered with yellow granules to your liking.
It's an unusual "decorative" appearance; it's certainly an attention getter. However, the granules soon
dissolve after a few waterings.
Preen also comes with a fertilizer, Preen 'n Green©. I have not used it. There's really no reason
why not, other than perhaps I'm just old fashioned and like to apply my own fertilizer.
Miracle-Gro also markets a weed suppressant. It contains the same chemical, Trifluralin, and
concentration, 1.47% as in Preen.
A chemical weed suppressant covered with pine needles would seem to be the ideal combination
to prevent weeds and to deter slugs.
Weed Control: A weed-free garden is beautiful to behold - but not easy to achieve. My
experience with chemical herbicides is very good.
Weeds in the spring can be killed, roots and all, using Roundup©, Monsanto Corp.'s well known
product. Another good product is Finale© sold by AgrEvo Environmental Health in Montvale, New
Jersey, and fairly widely distributed in the Delaware Valley.
In the past, many gardeners found that two applications of Roundup seemed to be needed to get
good results to kill some weeds, while Finale seemed to require just one. So last year, apparently to
compete better with Finale, Monsanto doubled the amount of glyphosate herbicide in Roundup from
0.96% to 1.92% along with the banner of "New - Twice as Strong, Fast-Acting Formula!"
Roundup and Finale come in squirt bottles. You need to take dead aim at the weed leaves,
hitting them squarely. What's critical is not to spray the hosta leaves. These are systemic herbicides that
quickly enter the plant. Even washing off the chemical soon after it's been in contact with hosta foliage
might still harmfully affect the plant.
So how do you spray weeds near hosta foliage? Very carefully. You need to shield the hosta
foliage from the spray using a piece of plastic or thick cardboard and newspapers (which are carefully
discarded afterward).
But often a more practical answer is, don't spray. Instead, I suggest this handy method that I've
found very useful.
Pour a small amount of the herbicide into a small plastic dish. Cottage cheese, yogurt and other
similar containers are a good size. Using a half inch-wide urethane foam paintbrush (readily available in
hardware and paint stores), saturate the foam tip with the herbicide. Then just paint the weed leaves
thoroughly. Try to wet both sides of the leaves if possible.
If the weeds touch or are very close to hosta petioles, try folding the weed stems down to the
ground away from the hosta leaves with your hand. Usually they won't spring back to their upright
position, and the herbicide can be easily dabbed onto the weeds without touching the hosta foliage.
Also, I'll use throwaway wood stakes to pin the weed leaves away from the hosta foliage.
Always dispose of the plastic dish and paint brush in a tightly closed plastic bag. And, wear
disposal plastic gloves when handling these chemicals.
Although the herbicides start to work in a matter of hours, it takes about a week or so to see
notable visual dying of the weeds. Have patience.
Dividing Clumps: This topic is covered in another article in this issue. See "Dividing Hostas in
Springtime by Bob Solberg.
Bob recommends dividing hostas in August or early September at least 30 days before the first frost
date. See his article, 'Divide Your Hostas in August or Early September," in the Summer 2001 (Vol. 10,
No. 3) issue of the DVHS Newsletter, page 4. WIP Editor
