Garden Calendar

 Everything in its season.  Even though I have been waiting to get started working outdoors there are sometimes when I realize that I've forgotten to get something started on time.  So I've taken this opportunity to review some of the key activities that I do, or should do, to manage my landscape over the year.

WINTER

Planning

As the growing season winds down, winter is a good time to reflect on the past season and decide what to do in the coming year.  Every year I sketch out a plan for the vegetable garden so that I can keep track of what I'm planting and when.  I can refer back to these from previous years to keep track of crop rotation.  This way I can ensure that I don't keep planting tomatoes in the same place, for example.

This was my 2024 garden plan.  I made notations about planting dates,
particularly for the corn where I staggered planting dates over 6 weeks.

Seed Starting 

If you are planning on growing plants from seed, particularly native species, many of these require a pretreatment in order to germinate.  In many cases this is accomplished by storing the seed under moist, but not wet, conditions in the refrigerator for 30 to 60 days.  This is referred to as cold-moist stratification.  It is meant to simulated conditions that a seed would experience in the wild. Prairie Moon Nursery has a Germination Guide for all of the seeds that they sell.  

Winter sowing is another method that is gaining popularity.  This is essentially direct sowing of the seed in a potting mix early in winter and leaving these containers outside to experience near natural conditions and break dormancy. Some advantages of this method are that the seed is already in soil so that they will begin growing when they are ready and you don't need to mess with grow lights and temperatures after you sow your moist-stratified seed.  See this post on Winter sowing I did a while back.

Direct sowing in the garden is also an option but I've had poor luck with this since it requires a perfectly prepared seed bed and protection of predators (birds) to get a good level of germination success.

Big Projects

If you are thinking of having work done winter is that time to get with landscape professionals.  They will have more time to work with you on designing and planning your work than if you wait until the spring.

Invasive Species Management

Winter is also a good time to eliminate many invasive species from your landscape.  In my previous blog post I listed some of the invasive species that could be addressed in the colder months.  These are mostly woody vines and shrubs.  I've been making progress against garlic mustard and Japanese honeysuckle by doing spot treatments with glyphosate in late winter, when temperatures are above 40°F.

Soil Tests

Winter is a very good time for doing soil tests as long as the soils are workable and you can take a proper sample.  By getting the results back before planting season begins you can make any adjustments well ahead of when plants go in the ground.  Winter is a particularly good time for applying lime, if needed.  Melting snow and wet weather help the lime to slowly infiltrate and do it job neutralizing excess acidity and increasing calcium levels. It may take 2 months for an application of lime to be effective.  See this link to the University of Delaware's soil testing lab.  

SPRING

Invasives  

In spring, when the forsythias are starting to bloom, is an optimal time to treat lawns with preemergent herbicides to control crabgrass, but more importantly to me, Japanese stiltgrass.  The blooming forsythias are a sign that the soil has warmed enough (55°F) that warm season grasses, like stiltgrass and crabgrass are breaking dormancy.  I have been doing this pre-emergent treatment for x years and have nearly eliminated stiltgrass from my turf, and reduced the amount of seed flowing into the surrounding woods.  I use a degree-day tracker, like the one from Michigan State, to optimize the timing of the treatment.

Forsythia and pussy willow (Salix discolor)
blooming at the beginning of April 2023

March into early April presents a window of opportunity for treating lesser celindine, Ficaria verna.  April is also when garlic mustard is putting on a growth spurt and producing flowering stems.  This is a very good time to pull these plants as long as the soil is loose enough to allow removal a most of the roots.  (If plants are actually in bloom the flowering parts need to be disposed of, otherwise even though they have been uprooted, they may still go to seed.)  

Ticks

Another early spring activity on our wooded property is to put out 'tick tubes'.  These are tubes with cotton balls treated with 5-7% permethrin, by weight.  The idea is that white-footed mice collet these for use in their nests.  The permethrin will kill any tick larvae present on the mice, thus reducing the spread of Lyme disease.  I mark each location with a landscape marking flag so that I can check if any cotton was taken from that spot.  I repeat the placement of tubes in late September hoping that the mice will take them into their nests over the winter.  I make my own tubes, but they are also commercially available.

Pruning

Late-winter to early spring is the time to start pruning summer flowering shrubs and plants that bloom on new wood.  For me this is mostly smooth hydrangeas (Hydrangea arborescens and cultivars). Spring blooming plants, like Azaleas, hollies, and big-leaf hydrangeas, should not be pruned until after they bloom, otherwise you will be removing flowering buds.  Fruit bearing trees are usually pruned in the spring, however each species has it's own particular timing to get improved fruit yields.  Apples, for instance are best pruned in late winter, in part to minimize infection of the cuts.  Any broken, structurally compromised or diseased limbs should always be removed as soon as possible.

Berry bushes like blueberries and blackberries really benefit from early season pruning.  To get improved fruits from wild blackberry I cut side branches back to 5-8 living buds in early March.  Last year I did a post of some of the wild brambles I have here.  

The four arrows indicate locations for pruning cuts on this wild blackberry. 
You can see that now, at the end of February, leaf buds are already swelling.

Garden Clean-up

As we are learning more and more about how we can help nature flourish in our gardens the advise is that whenever possible delay cleaning up the garden debris from last season.  Many pollinators and beneficial insects are overwintering in the fallen plant materials.  I will refer you to two links for more information on the hows and whys of delayed clean up: Izel Plant Blog and Penn State Extension.  In short if you can wait until early May, you will be doing a lot to help native bees and other pollinators.  Exceptions to delayed clean-up include plant diseases that overwinter in the leaf litter and insect infestations.

No Mow May 

No Mow May was started in England as a push to provide early season pollinators with flowers that are common in English lawns.  Blindly adhering to a no-mow-May program in a country with so many diverse climates and types of lawns as the US is often inappropriate.  To be useful, the lawn or property in question needs to have a population of plants with early blooming flowers that the pollinator population likes.   Depending on the climate the appropriate time for suspending mowing could be as early as February or into the later part of May.  If you have a monoculture of Kentucky blue grass there is little benefit to pollinators in skipping a month of mowing, there is just nothing of benefit there for them.  If you have a diverse ‘lawn’ containing native weeds like violets, self-heal (Prunella vulgaris), fleabanes (Erigeron sp.), spring beauties (Claytonia virginica) and the like, then allowing those to come into bloom would have a positive effect.  If you really need to mow, take the effort to mow around the blooming plants until they are done.  Lawns can also be interplanted with spring bulbs.  While not native, very early bulbs like Crocus, Chionodoxa and Scilla can add interest to an early spring lawn.  These bulbs have usually completed their growth and blooming cycle by the time the need for mowing kicks in.

I have been allowing this patch of Philadelphia fleabane
to develop without mowing.  It reaches peak bloom
in mid-May.  I usually mow it down in early June
after it sets some seed. When not in bloom plants survive
as low-growing rosettes.  

My recent experience with letting the lawn grow out late April through May was an increase in ticks. We are surround by trees and woodland edge habitat which makes the tick problem worse due to the higher humidity environments.  From what I've read ticks will not survive under low humidity conditions, so an open dry lawn should not be as much of a problem.  This year I will maintain the edge habitats at a lower level and try to avoid the lawn flowers.

While there is the oft repeated advice to never cut more than one third of the length of the grass blade at a time, I rarely let that force me to cut the lawn before I’m ready.  I can’t say that I have ever noticed a problem by occasionally letting the lawn get too long between cuts.  In those cases when I do, the biggest problem is the long clippings left on top.  A mulching mower can help deal with that.  All these problems are magnified on the ‘perfect’ lawn, where any imperfection becomes blaringly obvious.  In a diverse, multispecies lawn imperfections blend into the mosaic of plant colors and textures.

Plant the garden

If you are starting vegetable plants from seed you'll want to get them stared about 6 weeks before planting time.  Read the individual seed packets for more precise instructions.  Spring ripening crops like lettuce, spinach and peas can go in early.  Summer crops like tomatoes and cucumbers go in no earlier than Mother's Day, but I often wait until late May for tomatoes, especially when it's a cold, damp spring.

Spring and Fall are the best times for planting perennials, shrubs and trees.  Cooler temperatures and normally moister conditions help plants settle in before the stress of summer heat kicks in.  Fall may be a bit better for trees since they will have longer for the roots to get established.

Even before planting in the garden soil, you can plant in containers.  The soil in these warms faster in the spring and you can get a head start whether it be vegetables or flowers.  I often plant seeds for spring crops like lettuce, Swiss chard and spinach in early April in pots on our deck that has a good Southern exposure.  

Cutting back

Often referred to as the Chelsea chop  wholesale pruning of many perennials is from mid-to late-spring.  The name was coined from the Chelsea Flower Show in the UK which occurs in mid-spring each year.  When timed properly this leads to more compact, bushier plants with more blooms.  Cutting perennials back generally delays blooming by a couple of weeks, and gives shorter bushier plants.  By cutting half of a mass of plants back at one time and the rest a couple of weeks later you can effectively increase the blooming time for that mass by a few weeks.  You can also enhance the height differences in a mass back staggering the timing of the cuts or cutting some shorter than others.  You should finish the cutting operations by the end of June at the latest to give plants a chance to reach maturity  before the bloom season comes to an end.

The arrows indicate the two levels to which I cut back these masses of
goldenrods and asters.  This will also reduce plants flopping onto the pool deck.

 SUMMER

Pruning

Spring blooming shrubs can be pruned after they have dropped their flowers. Surprisingly Rhododendrons can take severe rejuvenation pruning and bounce back after a year or two.  So if you have overgrown rhodies blocking views in front of a window you can cut them back to a few feet tall and they will put out new shoot along the remaining stems.  Pruning can be done as need though the summer, but that chore should be wrapped up by the end of August to allow any new growth to harden off before cold weather sets in.  

Maintain New Plantings

Any newly installed plants will need extra care, particularly water, their first year in the ground.  Water as needed.  If you have established plantings, particularly native species, in the right locations these can be allowed to go dormant when conditions are harsh.  They will bounce back when temperatures moderate and or rainfall returns.  The same can be said of a lawn.  An established lawn with cool season grasses will want to go dormant in the heat of summer, this is natural.  It will bounce back.  As the saying goes: "Never teach a pig to sing, it's a waste of your time and it annoys the pig" (Robert Heinlein).

Control Invasive Species

Removal of invasive plants either manually or with judicious use of herbicide can continue through the summer.  If you are pulling invasive plants be aware of any seed that are present or developing and bag these so as not to spread the seed to other areas.

Deadheading

If you want to get more blooms from annuals or perennials, deadheading spent blooms is the future.  This guide from Garden Gate Magazine has a list of 50 perennials and whether and how to deadhead.  Deadheading will reduce the amount of seed produced in the garden, so if providing food for wildlife is important you may want to refrain from deadheading, particularly toward the end of summer.  Also leaving some seed heads in place can add interesting structure in the garden through the winter months.

Enjoy

Summer, particularly August, is when the landscape is peaking and there is actually less work to do.  Enjoy it!

Coastal Maine Botanical Garden

FALL

Planting

Fall is another good time to do new plantings.  Weather is cooling and there is normally more rain.  Mid-fall is usually a better time for planting trees, as there is less heat stress and root growth will continue as long as soil temperatures are in the the 40's.  

Invasive Plants

Continue to remove invasive species, but as before, be aware of any seeds that are present.  Fall is a particularly good time to do herbicide treatments on invasive trees like Tree of Heaven, Ailanthus altissima.  At this time sap is flowing down to the roots and  techniques like 'hack and squirt'  are very effective at concentrating a small amount of herbicide where it will do the most 'good'.

Deer protection

Here in the Mid-Atlantic the end of October brings on deer rutting season.  While deer are always browsing on plants, rutting season  is extremely destructive to healthy,1-4 year-old trees and shrubs.  Male deer rub there antlers on the trunks of young trees to remove velvet from their horns, stripping bark and flattening trees in the process.  They also will get very aggressive in mating season and seem to destroy plants as a way of showing dominance.  Welded wire fencing, plastic tubing and tree wraps are all helpful tools to reduce damage.  These some of these measures should be removed in spring if they cause the tree trunk to overheat or restrict growth. Fencing, cages and repellent sprays are useful for discouraging feeding.  

Here I have a 4" drain pipe spiraled around a sweet bay magnolia. 
Deer had severely rubbed the bark as high as the arrow. 
This was 5 years ago and the tree has recovered.

Here I have used plastic fencing to protect the bark from rubbing.

Ticks, Act 2

As the weather cools white-footed mice collect material for their winter nests.  This is a time that I put out a second batch of tick tubes.  Since I've marked each one with a colored marking flag I can check to see if any cotton remains from earlier in the year.  If there is still cotton, it indicates that no mice gathered material from that location.  In that case I will find another spot nearby that looks like better mouse habitat.  

Lawn care/Clean-up

If you feel the need for fertilizing your lawn, fall is the best time for a single application of a slow release fertilizer.  The nutrients are delivered slowly and are taken up and stored in the roots preparing the grass for regrowth in the spring.  Rather that using fertilizer I prefer to mow any fallen leaves into the lawn using a mulching mower.   Another option for fallen leaves is to move them into the garden or other area where they can serve as habitat for overwintering insects.  See the information links under Spring clean-up, above.  There are many reasons for putting off fall clean-ups; however, exceptions to delayed clean-up include plant diseases that overwinter in the leaf litter and insect infestations.

Review

Review what worked and what didn't.  Write down some notes where you can find them again.  You might think you'll remember, but there's a good chance you won't.

Spring Finds 2023

 

A weakened garlic mustard.  Arrows pointing out insects on
the stem and leaf and a weakened flower stalk.

While out evaluating the effectiveness of winter spraying and pulling up garlic mustard this spring I noticed aphids on the plants that I had not noticed before.  These might be the garlic mustard aphid, Lipaphis alliariae.  These are native to Europe but have been showing up in the US of late.  I first noticed these dark colored aphids on plants that had been sprayed with glyphosate.  As I became aware of them I found scattered populations on the untreated garlic mustard as well.  Plants that were heavily infested with aphids were not coming into bloom.  Fortunately this species is host specific, meaning it only feeds on a single host plant, in this case garlic mustard. If you see them you can report the sighting on iNaturalist or EDDMaps, a web-based app for reporting and tracking invasive species.  

Close up of aphids on a garlic mustard leaf.  Coloration and
markings are consistent with the garlic mustard aphid.

The aphids on this garlic mustard are
interfering with blooming.

The area to the left of the line was sprayed with glyphosate in late February. 
The effects of spraying didn't show up until the weather began to warm in April. 
This photo was taken about 2 month after spraying.

As I mentioned in my last blog post one of my to dos was to spray a number of invasive plants with glyphosate before the native species broke dormancy.  I was a little late in getting this done so I had to be very careful not to spray the emerging native plants.  It took a long time to see any effect of the treatments. It became clear where I had sprayed after the weather got a little warmer and the Japanese honeysuckle started greening up.  The sprayed areas were definitely browner.  However, there is new growth of Virginia creeper, ash seedlings and grasses.  The box elders that were covered with honeysuckle took some damage, but they are now beginning to leaf out.  The targeted spraying technique that I have been using limits damage of non-target species and reduces the amount of pesticide applied but it also allows a lot of target plants to be missed.  As practiced, it is one of several tools I use to control invasives.  Pulling, cutting and replacing are all important components in my battle. While not 100% effective using my technique, it did set back the early growth of Japanese Honeysuckle and garlic mustard and multiflora rose.  This spraying has little effect on Oriental bittersweet, which does not put out foliage until much later. The cut stump method seems to be more efficient for shrubs and climbing vines (less overspray).  I will try to do the spraying in November this year after most of the native have died back.  There are studies that indicate that glyphosate treatments for garlic mustard at that time are more effective than in the spring.

Rattlesnake, or common grape fern, has a distinctive triangular shape

While putting out tick tubes a week ago (this is nearly a month later than I had planned) I came across a fern I had not seen before.  It has distinctly triangular appearance, quite unlike the Christmas and wood ferns that are pretty common here.  A photo sent to the ‘Seek’ app on my phone identified it as rattlesnake fern, Botrychium virginianum.  This is one of the grape ferns, named for the clusters of sporangia on the fertile frond that may look like a cluster of grapes.  The fern that I spotted lacked a fertile frond.

A Christmas fern (left) and an unusual form (right)

The pinnae of this fern are distinctly toothed, many with spiny edges.

Another unusual fern I spotted was in a clump of Christmas ferns, Polystichum acrostichoides.  Usually the margins of the pinnae (leaflets) are nearly smooth.  On this fern the margins of the pinnae were distinctly toothed, many were spine-tipped.  The pinules do have the enlarged lobe at the base, common to Christmas ferns.  So this probably is a variant of the regular Christmas fern.

The blue-green foliage of these twinleaf plants forms an effective ground cover.

I have been working on finding native replacements for vinca in a dry shady location for quite a while.  One plant that continues to impress me is twinleaf, Jeffersonia diphylla.  While its native habitat is rich moist woods, it seems to have found a home in the dry shade of this driveway planting bed.  After taking a year or two to settle in it has been doubling its spread each year for the past 3 or 4 years.  The flowers last for only a few days in early spring but the interesting foliage persists until fall. 

The branching habit of this violet sets it apart from most of the others
growing here. The large, toothed stipules indicate that this is pale violet.

Springtime is when most of the violets come into bloom.  By far the most common here are, appropriately, common blue violet, Viola papilionacea.  So when I saw a white violet in the woods I stopped to examine it.  Besides the white color, what distinguished this violet was its branching flower stalk.  Most violets only have basal leaves.  Checking in my Newcomb’s guide led me to ID this as pale violet, Viola striata.  Canada violet, another similar white violet has yellow coloration in the throat of the flower and lacks significant stipules.

Some of the flowers in my early May lawn.  Most noticeable
 are the Philadelphia fleabane (native) and the bulbous buttercup (not).

 No mow May?  I still haven’t mowed yet this year.  I have been allowing the fleabane and other natives time and space to flower and go to seed.  However, this also allows bulbous buttercup to do the same.  There are several aspects of looking at the ‘No Mow May’ trend.  It is valuable if your lawn contains early blooming plants that benefit insects/pollinators.  Natives like fleabanes, selfheal, spring beauties and violets, can benefit the local insect population.  If your lawn is a near monoculture of turf grasses skipping the mowing in early season will save on gas, but do very little to help the pollinator population.

 

Saw lots of salamanders in the pool this spring.

After opening the swimming pool this past month I found about a dozen salamanders hanging out in the cold water, about 58°F.  Normally salamanders are tricky to get out, but these were relatively sluggish and were easily caught in the basket skimmer.  These were most likely red-backed salamanders, Plethodon cinereus.  At this size these were probably a year of two old, old enough to be looking for a mate.

 

 

 

Fighting Garlic Mustard with Fire? Or Something Else...

A couple of years ago I added a garden torch to my arsenal of tools to maintain the landscape.  Fire can be a natural and effective tool in controlling invasive species and is one of the better ways to maintain a prairie ecosystem.  But, fire can also get out of control and its effectiveness is diminished if it is not timed properly or its intensity is not sufficient to destroy the target species.  On the garden scale a garden torch is a good way to kill weeds growing in cracks in a drive or walkway.  It is also effective at killing young seedlings, particularly annuals.  I found it particularly useful for  for clearling plants away from the partially buried wire fence around the vegetable garden.  Perennials and established plants require much more heat to kill them.  For established weeds repeated burning 2-3 weeks apart may be necessary.  Though it seems counter-intuitive, flaming moistened soil is more effective at killing young plants and seeds than dry soil because the moisture helps conduct  the heat through the soil.

Here's my Benzomatic garden torch.  It is light weight and a good size to fit into tight spaces. 
The one pound tank lasts an hour or so, depending on how big a flame you use.  

I originally got my torch to use on Japanese stiltgrass.  While spring burning does kill the sprouts effectively, other plants are actively growing at this time and the fire will set those back as well.  Also stiltgrass germination occurs over an extended time period, so multiple burns would be necessary.  For stiltgrass in a cool season lawn, burning in late summer, while the perennial grasses are in summer dormancy, is very effective at preventing the stiltgrass from setting seed.

This success with stiltgrass got me to thinking about using the torch on garlic mustard, Alliaria petiolata.  Garlic mustard is a monocarpic biennial. It spends its first year as a rosette of deeply reticulated, reniform (kidney-shaped) leaves that builds up energy reserves in its fleshy white roots.  The following year it sends up a 2-4 foot flowering stalk in mid- to late-spring. It seems that winter time might be a good time to take out the garlic mustard.

Winter rosette of garlic mustard.

In the past when I have tried to burn garlic mustard I found I had to hold the flame on the plant for a long time before I could see much damage.  Before burning through a lot of propane, I decided to do a little research on using fire against garlic mustard.  The U.S. Forest Service has reports that document the effects of fire on a number of important plant species, including invasives.  Follow this link to the Forest Service report on garlic mustard.  A study authored by Victora Nuzzo for the Illinois Department of Conservation in 1990 compared the effectiveness of fire, herbicide and cutting for the control of garlic mustard.  They found that for fire to be effective it needed to be moderately intense and carried out in early spring.  Ideal burning conditions were often not available.  Herbicidal spray treatments were most effective in early fall and spring, timed for when native vegetation was dormant and thus less susceptible to the herbicidal effects.  One study out of Ohio showed that winter-time application of glyphosate when temperatures were between 25-45 F was very effective at killing garlic mustard rosettes.

Cutting plants after seed formation had begun in mid- to late-summer was very effective at reducing the number of plants in subsequent years.  Cutting at ground level resulted in nearly complete mortality, while cutting a couple of inches above the soil surface was only about 70% effective at killing the plant.  Since flowers and seeds continue to develop on cut stems, it is important to bag and dispose of all the garlic mustard cuttings.

Pulling mature garlic mustard is also very effective, and can be done anytime.  As with cuttings, if there are any flowers present the pulled plants should be bagged and disposed of.  While completely non-toxic, pulling garlic mustard is labor intensive (pulling and clean-up) and disturbs the soil.  This allows for the germination of additional seeds buried in the soil.

Here are some of the interesting garlic mustard facts that I came across while researching this post:

•        Seeds lie dormant for a year before germinating.  This means you may not see the effect of control measures on new seedlings until the second growing season.
•         Flowers are self pollinating; many are already pollinated before the flower opens.
•         Flowers can photosynthesize.  They can continue to mature to form seed even after they have been cut or pulled.
•        Plants are monocarpic.  They will continue to live until they set seed, even multiple years.
•        Seedling mortality is high, 80-90%, during their first year.  More effort should be expended on removing maturing plants particularly in late fall to early spring.
•       Of the common herbicides, glyphosate and triclopyr are very effective at controlling garlic mustard, 2,4-D is not.

So, Burn or Not?

So to answer the original question, should I use fire to control my garlic mustard?  The answer, for me, is no.  I will need to use a combination of tactics appropriate to the situation and season.  Winter spraying with glyphosate will be easier and more effective than fire at my location.  In the spring, pulling or carefully targeted spraying would be most effective.  And for those plants remaining in the late summer, cutting close to the ground or continued pulling will be in order.

To test this I will target spray with 3% glyphosate in a section of the woods in February if (when) we get a stretch of days in the 40’s with no rain and see how that compares to untreated areas.  (February seems a little early, but we are in the 60’s in early January, so plants may be getting woken up a few months before normal.)  Rather than blanket spraying I will try to target the spray onto existing rosettes.  One of the reasons to use target application is to avoid those few natives that are still in leaf through the winter. 

Some native plants that may look similar to garlic mustard rosettes include violets, Heuchera, Tiarella, and white avens (Geum canadense).  Ground ivy (Glechoma hederacea) and common mallow (Malva neglecta) are some weeds that look similar, but are not currently on my hit list.  (I found no studies that indicated that ground ivy is susceptible to herbicides in winter.  Based on that I wouldn't waste time and materials treating it in the winter.)

Compare the palmate lobed leaves with the deeply veined (reticulated), bright green leaves
of the garlic mustard.  Here, pulling is the only option for removing the garlic mustard.

The leaves of foamflower are distinctly lobed.  The vein pattern
is different from that of garlic mustard.

Golden ragwort has regularly toothed leaf margins and a more linear vein pattern.

White avens over winters as a loose rosette of leaves.  Though most winter leaves
 have 3 lobes, some appear roundish and vaguely similar to garlic mustard.

The leaf shape of common mallow is similar to that of garlic mustard,
but the vein pattern is different.

In areas where I am more actively managing the garlic mustard I will continue pulling plants through late spring (before flowering).  In late summer I will see if there is a practical way to cut the plants close to the ground without leveling the surrounding vegetation.  Otherwise, keep pulling!

This table summarizes the garlic mustard control methods mentioned in this post.

Summary of Garlic Mustard control measures

Method	Timing	Pros	Cons	Effectiveness
Fire	Late Fall to Early Spring	Non-toxic	Difficult to achieve ideal conditions; Need to keep under control	A good moderately hot fire is effective, but difficult to achieve.
Herbicide Spray	Dormant season	High kill rate; can be targeted; no soil disturbance	Spraying toxic materials; may affect non-target species	Dormant season spraying reduces damage to non-target species.
Cutting	Summer, after flowering	Non-toxic; cutting at ground level nearly 100% effective; minimal soil disturbance	Labor intensive; must dispose of stems/flower stalks; use of weed whacker causes collateral damage.	Very effective when done right.
Pulling	Anytime ground is soft and easily worked	Non-toxic; very effective as long as most of the root is removed	Labor intensive; disposal of pulled plants required once flowers are present; soil disturbance	Very effective