Tuesday, July 31, 2012

Iris Borer - Bacterial Soft Rot Control

Today, I noticed the Iris Borer (Macronocutua onusta) among some Bearded Iris (Iris germanica). Yellow to brown leaves and drooping foliage showed evidence of their presence. Unfortunately, this borer is known to eat all forms of Iris (Siberian, Japanese, and Bearded), but the Bearded Iris' large rhizomes generally can tolerate their devastation. Yet, today I was proactive in trying to rid the pest for good.

Here, the front leaves were flopping forward.
Hollow centres towards the base of rhizome.

I began to look further, inside the the centre of the plant to see blades of iris leaves with this streaking and damage.  I pulled on these and they came free easily, revealing a hollow centre to each segment.

Taking off the streaked leaves you can clearly see where small larvae have made their way into the base of each blade segment. They borrow between the blades of Iris leaves, tunneling down to the rhizome.

When you see this tunneling, please remove the entire leafy section, and break off the adjoining rhizome.

Pink bodied, with a brown shiny head.
Here I cut the rhizome root in half, and you see the tunnel and pithy excrement of the larvae. 

At this time of year (late July), you will see in the rhizome, a pink wiggler of a larvae. Quite large - spanning about 1 to 1.5 inches in length. These larvae hollow out the rhizome and eat the innards causing significant damage and Bacterial Soft Rot. This then can transfer to neighbouring rhizomes, making the entire plant collapse given time.

 The rot can become quite noticable, making the foliage droop or collapse as I saw today.

Here is the larvae as I removed it from the rhizome hide-away:

Remove and squish all these larvae, to prevent them from becoming adult moths. The larvae move to the rhizomes to feed and to pupate, becoming adult brown moths.

Adult moths will lay eggs in late August to September at the base of the Iris to start the whole process over again.

Control:  The best control is a thorough tidy up at this time of year. Remove any streaking foliage, and dying leaf blades. Examine any blades and rhizomes for tunnels.

Divide your Iris every 2nd to 3rd year. This should be done in late August - September. By doing this, you take notice of the rhizomes and also gives the plant room to grow more abundantly.

In spring, when the foliage reaches about 6 inches tall, the eggs of the Iris Borer will have hatched and tiny larvae will begin to bore through the blades. You'll see pin-pricked sized holes with some streaking. Squishing tunnels or removing the damaged leaf blades will reduce their numbers significantly.

Thoroughly keep your iris free of debris in August/September. This will deter the adult moth from laying eggs at the base of the plants. In late fall, clean up all the dead and dying leafy blades from frost damage. This will help expose overwintering eggs that you may have missed. Destroy and don't compost any of the foliage.

Keep an eye on your iris throughout the growing season for signs of damage.

Hope that helps!

Monday, July 23, 2012

Amaryllis Update

July 12th
Given the unseasonably HOT start to the summer, my Amaryllis plant is starting to turn already. Usually this starts to happen around August/Sept - so, we'll see how much energy has been returned to the bulb.

Here is my previous post regarding the care of your Amaryllis.

July 17th
July 19th
The time when the plant expires, is when each blade of the Amaryllis foliage will begin to wither and wilt as you can see.  Allow them to completely wilt, so that the leaf can come easily free from the bulb.

July 23rd
Continue to water the Amaryllis still at this stage, but only to keep the bulb from drying out.

It takes a week or two for all the leaves to wither back.

Once all the leaves have withered, remove the bulb from the pot and gently tease the soil away from the roots. Keep as many of the roots as you can.

As you can see, there is a small leaf emerging from the bulb top. It looks familiar, doesn't it? Many amaryllis bulbs look this way in the fall when they are available to purchase. Not to worry, that just means the bulb wants to start off fresh again.

Right now, I am placing the bulb back into the empty pot (composted the used soil) and I will place it in my cool, dark laundry room for 2 weeks or so. I will keep an eye on it throughout the next weeks. Once the roots go limp and brittle, I will remove as many as I can without damaging the bulb. Once I've tidied up the bulb (don't leave too much debris, or mold may develop), I will place it in a bowl of vermiculite to keep it dry. Keeping it in a cool dark place until early November, when I plan to start the process all over again!

Hope yours stores well. What other medium do you store your bulbs in?

Here is my post on how to start the process all over again. Enjoy!

Thursday, July 19, 2012

Another batch of Compost ready: 6 weeks

Left side, ready. Haven't added scraps in last 3 weeks.
I am brimming with satisfaction over my Dual Batch Rolling Composter. It's been another six weeks, and I can report another completed batch of compost is ready.  This heat wave has certainly accelerated decomposition.

Great stuff. I wish you could smell it. So fresh.

Some helpful hints I've learned along the way since my previous 2 composter posts:

  • If you add lots of kitchen scraps, avoid adding too many (sugary) fruity bits. I added soft cherries and grapes, only to find I had a large quantity of ants invade one chamber.
  • Adding kitchen scraps daily adds adequate moisture. No added water is necessary, unless you add a lot of dry brown debris.
  • I found spinning the rolling bin should be done only once a week, if not less. Rolling it thoroughly, rather than one rotation or so is better than just once over.
  • Cutting up thicker, leafier material aids the process.
  • Do not fill the chambers to full. Fill about 2/3rds. This allows for air circulation and better tumbling of contents.
  •  Filling the chamber nearly full with green waste will not give you a full chamber when done.
  •  Keep the vents open.

Right side - scrap side
Since the ready chamber is not yet full, I will add compost from the kitchen scrap side to the other ready side, in order to bulk up for a full batch in September. I plan to top-dress my garden with the left chamber's contents, leaving the right chamber to carry me through the autumn months.

Right chamber: not ready...but getting there!
So pleased.

Monday, July 16, 2012

Signs of plant drought (heat) stress

Evidence of heat and drought stress is now clearly seen on plant material here in the GTA.  This heat wave since June is taking its toll. What little snow we had over winter, and with our unusual warm spring - trees, shrubs, evergreens and perennials now bear the brunt of this drought.
Brown grass under tree (with fallen tree leaves)

Working in gardens every day, the signs are quite noticeable in advance, yet at my part-time garden centre job, customers bring in samples - not realizing the damage is from drought.

This baffles me.  I figure, if the lawn is yellow and gone dormant, don't you think the heat will have an effect on your other plants?

Please, water DEEPLY about once or twice a week, rather than each night with your hose end sprayer. Leave a sprinkler on for at least 2 hours in the morning. Leave a cup out under the sprinkler to see if it fills half way. The cup is a good indicator that at least 2 inches of moisture will go down deep, where roots are needing it.

Aerate your beds by giving them a good light scratch, so moisture doesn't run off the soil that has been baked to a hard crust. A good cultivation will allow the water to absorb more quickly.

For trees, take a garden fork and jab all around the drip line of the tree to aerate the area beneath. This will help water to penetrate down to the tree's fibrous roots.

Drip-line of tree
Interior yellowing of leaves on Tilia cordata
Curled leaves on Prunus Shubert Chokecherry
 A good 4inch layer of mulch around the drip-line of trees is a good practice. Especially for newly planted or establishing trees. Just be sure not to mulch the area around the trunk. Keep that area free, so the mulch won't rot bark. (Just think of a wet band-aid around your finger...:)

Some tell-tale signs of heat stress:
  • curled leaves
  • dropping leaves
  • yellowing interior foliage
  • dropping fruit
  • bud drop (on late flowering Rose of Sharon)
  • burnt edges
  • heavy seeding
  • insect infestations
  • speckling on foliage

Scorched Hosta leaves

Burnt edges on Brunnera

Over abundance of seeds on this Acer negundo

I can't stress enough regarding watering. Even with the thunderstorms and intense rain for a few minutes we had last night, the water would not of penetrated deeply enough for roots after such a lengthy dry period. It just runs off down the sewers.

Everyone wants a green lawn. Instead, focus your watering on trees and shrubs and less on the lawn. After a good rain or so, the lawn will bounce back quickly. Trees and shrubs won't. They need our HELP!

Remember:  A fully grown tree may lose several hundred litres of water through its leaves on a hot, dry day. The same tree will lose nearly no water on wet, cold, winter days. Almost all water that enters a tree's roots is lost to the atmosphere but the 10% that remains keeps the living tree system healthy and maintains growth.

Water, water...water!

Thursday, July 12, 2012

Japanese Beetle - Popillia japonica

The Japanese Beetle
One of the most destructive beetles has come out of hiding (pupated). The ever multiplying Japanese Beetle is invading the garden once again. Like most bugs this year, their populations are quite numerous for this time in July.

I really shouldn't complain about them. I pretty much have a job because of pesky bugs and weeds. Although, seeing their skeletonized aftermath, there's nothing but frustration brewing under the collar. I can't help but wonder what our gardens would look like if the Japanese Beetle never made the journey over the ocean ages ago.

Photo Source: Kentucky College of Agriculture
The only way we can control them properly, is to know their life cycle. Kentucky's College of Agriculture has this fantastic beetle life cycle diagram. Once you've seen them in the garden, you know how they populate quickly. Usually I find them in pairs, if not in masses - reproducing in action. :) At least that's one good thing, you can collect them rather easily.

In late July and early August, the hotter the weather the more they congregate on the top of plants - near blossoms or tender leaves.They start at the top, working their way down the plant. A group of beetles attracts more beetles. Once, I counted at least 20 beetles on one unfurling rose.The beetles are most active during the hottest part of the day (noon-to-three).
Eating Parthenocissus quinquefolia - Virginia Creeper

One of the reason's they are so rampant, is because of North America's love for turf. They overwinter as grubs in turf. When roses, fruit trees and other food interests are closest to turf, the more they get attacked by the beetles.


Congregating on top of vine
1) Collect as many of the beetles first thing in the morning. They are sort of "slow" in cooler weather. Sluggish and not flying away when you collect them. However, they may not be seen as readily. They are the most active during the heat of the day, so you may have more success in finding them. Squishing them between your fingers is best.Collecting is quite effective if you are persistent and thorough. Doing so prevents them from laying eggs in turf close by. I usually clap my hands quite harshly right over the grouping of beetles. The smash stuns them and they generally die as a result. It's hard to collect dozens in one spot. Some fly away and come back.
The beetles make dozens of holes, until most of the leaf is gone.

2) Japanese Beetle Traps:  There are different kinds on the market. Some are pheromones mimicking females - attracting males and others attract the beetles with a food source. Both are quite effective. As when two or more beetles are gathered, more come round.  Sometimes, unfortunately - the traps attract more Japanese Beetles to your garden from the neighbourhood than before. It's best to place the traps downwind at the furthest direction away from the path of highly edible plants that the beetles love. In my experience, walking slowly by your roses or infested plants with the Japanese Beetle trap, will encourage them to follow you. As I was hanging the last trap I placed, about 5 beetles gathered at the top of the trap before I even fully secured it. It works.
Breeding machines!

Another control is planting material that isn't attractive to the Japanese Beetle. Know the plants that Japanese Beetles devour: Here are 2 comprehensive lists

Be persistent and look for the typical hole markings they leave behind.

Best of luck!

Saturday, July 07, 2012

Limited Space Vertical Gardening

Humber College Urban Homestead Display

At Canada Blooms earlier this year, I got a glimpse of some interesting vertical gardening techniques.  Living walls and stacked containers demonstrated you can still garden even though one might not have a large area to work with.

Lee Valley's Stacking Pots

 Lee Valley has these wonderful stacked containers which I think are ideal for herbs.

Stacking Pots and accessories
Having little pots scattered about would reduce space and increase clutter - this idea lets you get a totem effect. Each stackable pot has 3 exposed planting areas, with a shared centre chamber, ideal for roots to spread and for adequate water retention.

Or how about this Wall Garden method: 
Lee Valley Wall Garden Container

Plant stands are also ideal. I've refurbished a stacked arrangement of sorts from reused items. I found this old plant stand at the end of someones curb, put out for garbage. I took it home, sanded the worst of rust away and spray painted it with rust-proof Tremclad. Functional waste diversion ;) Now it holds some of my herbs.

Even in shade I manage to grow tomatoes. Here I placed my grape tomatoes in a moveable pot (on wheels) to maximize sunny spots (which move through the summer). I also extended the tomato cage with bamboo hoops. Now the tomato stands over 6 feet, and currently over 8 flower batches are in the progress of maturing to fruit in the next few weeks. Yay for vertical growth!

I added more obelisks to my containers and trellises to my garden, in order to achieve more height.

There's a lot of creative ways to maximize space.

Wednesday, July 04, 2012

Euonymus Scale - Unaspis Euonymi

I don't think there's an Euonymus fortunei plant out there that hasn't been pestered by this insect.  Variegated, ground cover, topiary - they all can get it. Unfortunately, when folks first notice the plant covered with scale, it's at a point where it is so difficult to get rid of them.

Euonymus scale (unaspis euonymi) is a sap sucking insect that stays under the radar so to speak, until population levels peak - giving away their secret.  They begin to hide on rougher bark branches (towards the mid-inside section) of the plant, reaching newer growth once the new buds begin to break in late early May. Hiding underneath new leaves, they begin to develop multiple life cycles as they populate the plant. Males are white and the females (slightly larger) are grey. They have a juvenile crawler stage which are usually an orange-yellow colour.

Scale fixate themselves, sometimes several insects deep when infestations are bad. When the plant is completely covered, one can take a sharp tool and scrape quite a thick coating of scales off the euonymus branches. It's quite gross, really.

What to do when you see this:

1) Where you can, prune out and destroy infested branches or plants before the young crawlers emerge. Pruning is even beneficial just by removing adult scale numbers. Yet, if the plant has lost many leaves, this becomes difficult to manage.

2) Insecticides are virtually useless and ineffective, unless timed properly.  They are only useful when they are applied at the onset of infestation and at the overwintering adult and the crawler stages. This can be difficult to time.

3) Dormant oils: this is an effective method to coat and suffocate the female scales that are filled with eggs.  In order to work, the oils should be applied in early spring or late fall, when the plant is dormant and when temperatures are cooler.  Branches, stems and leaves must be thoroughly coated in order to suffocate the overwintering adults. Using oils can burn leaves if applied too late towards hot summer months, so be wise in applying.

4) Water.  I can't say enough about water. Watering the plant will help give the infested euonymus ample moisture to draw from, since the insects are sucking its sap.  But water is also a wonderful way to help dislodge the insects from the host. High pressured water from a simple garden hose can reduce numbers significantly, with a little coaxing from a brush or your hands rubbing over the stems as you spray. It's an arduous task, but one I've used myself during the summer months. There's nothing more dis-heartening than to see the scale bounce back in numbers after you've treated the euonymus bush earlier in the season. Spraying the bush with water every two weeks does significantly reduce the insects in number, giving the plant breathing room to take a rest from the infestation.  I've specifically sprayed after a good pouring rain. The scales soften their grip in rain and the hose pressure blows them off. You'll notice their floating bits in puddles around the bush once you've been thorough.

5) Don't bag or cover your euonymus over winter. I've seen it time and again, when folks think that euonymus need covering. What you're doing is limiting the harsher exposure of temperatures on the plant, protecting overwintering female scales. Frost kills a lot of insects, and bagging will just keep them cozy for spring to arrive. Also the bag doesn't allow snow, rain and the elements that help wash down the bush. Euonymus benefit from natural elements, just not salt!

Unfortunately, once you've had scale, it tends to be a recurring problem. No doubt your neighbour has these same bushes, with the same problems - so inevitably you'll have them visit again.


Euonymus scale love hot temperatures. Making sure your plants are not in hot areas is a preventative practice.  Don't plant them next to a brick wall. This is a fantastic breeding ground for euonymus scale. Watering your bushes in drought conditions makes the euonymus stronger and more apt to fend itself away from the a light insect attack. Spray with water occasionally during the summer months. The is a key preventative.

Regular pruning is necessary, to promote aeration, new healthy growth - bringing vigor back to the plant. Don't just sheer the plant into a ball or round shape. Get inside the bush; prune out dead or weak branching. Allow air and sunlight to reach into the crown of the plant. This allows euonymus to recover.

Don't plant multiples close together. Space the euonymus plants apart. That way, if one really gets scale bad, it's not going to jump to the next.

Watch:   keep your eye on especially euonymus leaves. Watch for yellowing areas, stickiness, loss of vigor and leaves falling in summer. These are all SIGNS that point to an attack.

Persistence works in the end.

Here are also other plants that can also be pestered by Euonymus scale as well:
  • Buxus, boxwood;
  • Celastrus scandens, bittersweet;
  • Hedera helix, english ivy;
  • Ilex, holly;
  • Ligustrum, privet;
  • Lonicera, honeysuckle;
  • Pachysandra terminalis, Japanese Spurge (groundcover).

Be proactive. Always check every season for signs...

Tuesday, July 03, 2012

Extending Dianthus x barbatus chinensis Bloom

Photo from Ball Seed Company
I love Dianthus x barbatus (chinensis). It is usually grown and sold as an annual form of Dianthus, but it has perennial (biennial) longevity with proper care.
In its first season, you enjoy endless bloom from planting til frost is common. Overwintering is typical, with a robust bloom in early summer. Yet, once June rolls around - they look spent like this:

Gather the spent flower stalks and cut back about 2-3 inches off the top, leaving about 4-5 inches of green growth.

This removes the seed heads and stalks, forcing new growth from the leafy area beneath.

Hedge hog hair-cut!

This cut will initiate new growth, which will bear new flowers in a couple of weeks. I used an all purpose water soluble fertilizer, just to give it that extra boost.

It may look severe, but it will extend the bloom until frost.

I have overwintered Dianthus x barbatus for up to 4 years by doing this each year. After that amount of time, it generally fizzles out and I replant a new lot.

Sunday, July 01, 2012

Maturing Perennial Planters

May 15th, 2012
This is the fun bit about using Perennials in planters. Their constant change, boosts the planter - adding different textures throughout the summer to your display.

1 1/2 month later:
July 1st, 2012

In mid-June, I added discounted annuals, to give a spot of colour throughout the summer. With 1 Dragon Winged Begonia, 1 Dusty Miller and 1 Victoria Blue Salvia (back behind the Begonias).

Soon the Astibe's will loose their colour and the hosta flowers will wither, but the Rudbekia will begin to flower and the Salvia will come out of hiding - extending the season until September.

Not bad, for dividing perennials from your garden.
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