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Archive for March, 2016

Grass growing in the daylilies

Grass is nice.

Most homeowners crave a beautifully manicured, lush carpet of turfgrass. The sea of thick, green grass surrounding the Viette home is the envy of visitors who come to wander through the extensive gardens surrounding their home.

Grass has swallowed up these tall bearded iris

Grass has swallowed up these iris

Yes, grass is nice – when it is growing in your lawn. It’s not so nice when it invades your flower beds and mixes in with your perennials, shrubs, and trees.

What do you do then?

One of the worst of the grassy weeds is Bermudagrass; aka. wiregrass. This  warm season, perennial grass is often used as a turfgrass in southern zones because it is tough and durable and quite drought and heat resistant. The problem is that it is a very aggressive grass and can quickly spread into flowerbeds if it is not kept under control. Even if you don’t have a Bermudagrass lawn, this invasive grass can take hold and overrun your gardens.

Other perennial grasses that can infiltrate cultivated areas are Johnsongrass, quackgrass, and perennial ryegrass.

Annual grasses like crabgrass, barnyardgrass, and annual ryegrass can also be major headaches in flower gardens.

How do we get rid of it?

The problem is killing the grass but not the desirable ornamentals. Glyphosate (Roundup) can be used but it is non-selective and you have to be exceedingly careful not to get any spray on your plants. This is difficult to say the least and impossible in cases where the perennials are growing (or trying to grow) through a sea of invading grass.

Sethoxydim selectively targets grass but will not kill broadleaf weeds like this field pennycress.

Sethoxydim selectively targets
grass but will not kill broadleaf
weeds like this field pennycress.

Luckily, there is an answer – a selective herbicide containing the active ingredient sethoxydim. It can be found under the trade names Poast, Segment, and Vantage, among others. Bonide Grass Beater contains sethoxydim and can be found in most full service garden stores.

When applied according to the label instructions, sethoxydim can be sprayed over the top of most non-grass perennials, shrubs, and trees without harming them. It does not kill broadleaf weeds or sedges (sedges are not grasses), but it is ideal for post-emergent control of both annual and perennial grass weeds in your flowerbeds.

An example of how it works …

At Viette’s, we have had some serious problems with grass taking over a few large sections in several of our daylily fields. In the past, we have used glyphosate to spot treat between the rows but this year, grass came up right in the middle of the rows completely surrounding the clumps of daylilies. It was pretty bad! We had to do something or the grass would crowd out the plants.

Grass growing throughout a row of daylilies

Grass growing throughout a row of daylilies

Our field manager and his helper used Segment (13% sethoxydim) to spray these patches of grass in the fields. Because daylilies are listed as tolerant to sethoxydim, they were able to spray right over the daylilies without harming them. This is ideal for post-emergent grass control in our fields.

Three days after spraying, the grass begins to burn back.

Three days after spraying,
the grass begins to burn back.

Three days later

Three days later

The label on this herbicide is extensive and it is important to read and follow the instructions. The label includes a long list of tolerant species of perennials, shrubs, and trees. It can even be used in the vegetable garden when applied according to the label directions.

The results were pretty striking …

14 days later. The green patch on the right was skipped. Since there are no daylilies in this area, glyphosate will be used to kill this grass.

Fourteen days later. The green patch on the right was skipped.
Since there are no daylilies in this area, glyphosate will be used
to kill this grass. The daylilies have grown well – no ill effects!

After 14 days. You can see where Bo edged this 5-row bed. The results are evident!

After 14 days in a different field. You can definitely see where
Bo edged this 5-row bed. The results are evident!

Pretty good results!

It did a pretty good job eliminating the grass!

The daylilies look healthy and are growing well. Luckily I can’t say as much for the grass! Now they can go back through all the fields and spot treat the broadleaf weeds with glyphosate. The fields should be in pretty good shape for the rest of the season!

Until next time – Happy Gardening!

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Crocus are blooming

Male spring peeper calling; photo credit Jack Ray

Male spring peeper calling;
photo credit: Jack Ray

The other night as I drove past a small pond on my way home, the chirping of the spring peepers was deafening! But I was happy to hear them!

Spring is near!

The peepers are singing, the crocus are blooming, and the daffodils are beginning to open! It seems that spring is slowly creeping into the Shenandoah Valley.

It has definitely been an odd winter this year with some very warm stretches mixed in with a few very cold periods. Some perennials have been fooled and many broke into growth earlier than they should have.

In late January, we received the following question via our Discussion Board:

Hosta damaged from a late freeze can be cut back

Even hosta damaged from a
late freeze can be cut back

I am in Toano, Virginia. We had an unusually warm start to our winter. As a result, my blueberries bloomed, my peonies started to come up as did my daylilies. Some of my daylilies never really went dormant. I covered the daylilies and peonies with pine straw but the daylilies grew almost 6 inches. Now the leaves are burned and chewed. Can I cut the leaves back to the ground now or [should I] leave them alone?

This type of plant damage is not unusual but it normally occurs in the spring when a late freeze damages the tender new spring growth. It’s a bit crazy that there was this much growth during a warm spell in the winter but, as we all know, it was a crazy winter!

Freeze damage on daylilies resembles insect damage.

Freeze damage on daylilies
resembles insect damage.

Here is my response to the question:

Yes it would be fine to cut the damaged foliage of your daylilies back. You can cut them right to the ground. The “chewed” leaves are probably a result of freeze damage rather than damage from a chewing pest. Re-cover the plants with the pine straw after you trim them back.

Pine straw makes a great, long-lasting mulch and the daylilies and peonies will grow right up through it.

Cut Liriope back before growth begins in spring

Cut Liriope back before
growth begins in spring

March is also a good time to trim back the old foliage of some of your evergreen perennials – especially Liriope, Helleborus, and Epimedium. It is so much easier if you do this before the new foliage begins to grow. You can pretty much just gather up the old leaves in a bunch and cut the stems close to the ground. Just be careful that there is no new growth in the way of your shears before you snip!

The old fronds of evergreen ferns should also be cut back now. Last weekend, I trimmed the old foliage from my Dryopteris, cinnamon ferns, ostrich ferns, and Christmas ferns.

Trim back old fern fronds before new growth occurs

Trim back old fern fronds
before new growth occurs

The crowns of these ferns were still firm and tight but the fiddleheads will soon begin to pop up and unfurl. After that, it will become harder to clean up the old foliage without snapping off the tender new fronds.

Ornamental grasses should also be cut back now. This is another group of perennials that is important to cut back before new growth begins. One of the easiest ways to do this is to cinch the old foliage together with twine or a bungee cord and use hedge shears to cut the clump back near the ground. Since it’s already tied up, you can just carry the whole bundle out of the garden. Nice and neat!
Here is a video showing just how easy this method is.

Oh and don’t forget!

Mark pruned this overgrown lilac back to the ground.

Mark pruned this overgrown
lilac back to the ground.

If you have some shrubs that have outgrown their space, now is the time to do any heavy rejuvenation pruning. This can be done with boxwood, holly, yew, rhododendron, azalea, and any others that have dormant buds in the bare wood. Even spring bloomers like overgrown lilac and forsythia can be pruned back hard to rejuvenate them and improve blooming, in addition to getting them back to a manageable size.

Normally, spring blooming shrubs are pruned after they finish blooming but severe pruning, where they are cut back hard (sometimes to the ground) is best done while they are still dormant in late winter or early spring. Of course you will sacrifice the bloom for the season but they should bounce back and bloom even better next spring or maybe the spring after.

Winter is on the way out! It’s time to get back in the garden!

Until next time – Happy Spring!

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