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Tuesday, March 26, 2019

March 26, 2019


Hi gardeners
This tulip is called 'Orca'

It’s a lovely spring day with lots of sun and birds singing here today.  It’s a bit chilly, just above freezing, but we have a warm up coming.  The robins are back now and our summer resident flock of turkey vultures are soaring in the blue sky.  I still haven’t heard any frogs and our pond is still mostly frozen.  And still no outside flowers! Some people to the south a few miles are reporting snowdrops and crocus in bloom but not here!

Last year the crocus didn’t bloom until April 2nd so I guess we aren’t behind last year. But in 2017 they bloomed March 21st and in 2016 by March 9th so the trend appears to be later springs. The amur honeysuckle is showing green bud tips, and grass is starting to green up so progress is being made.

If you live in the country, you know how bad the roads can get in the spring.  Ours are the worst I have seen in many years. The mud is a foot deep in places. Our driveway is just soil- in summer it basically looks like lawn as it doesn’t get used a lot. This spring the ruts are so deep I have gotten stuck backing out.  I hate to add gravel because it shoots all over when you drive over it with the mower.  I’m hoping it dries up enough this week to fill in the ruts with soil.

My garden chore this week will to be to get posts in for the electric wire I am going to run across my front flower beds, so the deer won’t eat the tulips, hosta and daylilies coming up.  I’ll use small fiberglass posts and thin wire and it won’t be too visible after things get growing.  I can usually take it down later in spring when the deer have plenty to eat. 

I may have to use black netting in some beds to keep deer out.  Wednesday and Thursday are supposed to be mild and sunny, so I’ll be outside starting that project and doing some light clean up.  It’s nice to be able to work outside again but I wish I didn’t have to devout so much time to deer protection.

I also have to cut out some black walnut trees from various beds and trim back the wisteria.  Which leads me to: is it time to prune yet?

Spring pruning and clean up

It’s been a long hard winter but some of us are finally getting outside and starting to clean up the garden.  Gardeners may be thinking of pruning off those dead looking branches and cutting back stems of perennials left over winter.  But don’t be in too big of a hurry to do that pruning and removal protective mulches.

It depends on where you are of course, but we still get some winter weather in April here in Michigan (zones 3-6) from time to time. If you remove winter killed wood from plants too early a hard freeze may further damage the plant. The dead areas have a protective effect on the live wood below them. Some of you are lucky enough to live in warmer planting zones and maybe your freeze danger has passed. So, when is it safe to prune off winter damaged plant material?

Redbud blooms before most of it's leaves emerge
A good indication of when to remove winter killed wood on plants is when you see buds swelling on similar plants or on that plant itself. Consider where the plants are- plants by the house may have buds swelling earlier than those out in the open for example. And remember, all species of plants don’t leaf out or flower at the same time. Amur honeysuckle and some willows for example, leaf out very early.  Catalpa and walnut trees are late leafing out. 

Some plants bloom before you see leaves.  If the plant is young and not blooming age, you may see swelling buds on older plants before the non-blooming age plant. Many fruit trees, ornamental pears and crabapples, maples, redbuds, witch hazel, and magnolias are examples of plants that bloom before they get leaves. (In some years weather may cause leaves and flowers to emerge together.) Compare the same species at the same maturity if possible. 

If you have no similar plants, you could also ask an experienced gardener in the area if your plant species should have swelling buds or leaves at this time.  If the trees are leafing out and the grass needs mowing in your area most plants should at least have swollen buds. It’s probably safe to prune off dead parts.

Determining dead wood/stems

Winter killed woody stems may look dark brown or black and shriveled. If there are buds, they are brown and shriveled. Healthy areas will have green stems or have light brown but firm, smooth looking stems/branches and should have buds swelling if temperatures have been above freezing for a few weeks.
You can take a bud off and open it, if its green inside – or has a flower inside- it’s alive.  You can also scratch a small area of stem with your fingernail and see if there is green tissue underneath. A branch that snaps instead of bending is dead. 

If you are unsure what is dead, leave the plant a little longer and examine it a week or two later. Some plants are just hard to determine as to whether there is life left in them. Patience is the key to gardening. Pruning a little late is better than pruning too early and taking off healthy wood or causing further freeze damage below where you cut.  You can always prune dead wood off later, but you can’t replace the living parts you pruned off.

When you do begin pruning you may want to prune short pieces off at a time, checking the end left on the plant to see if any green tissue shows just under the bark layer. If you see green the branch is alive at that point.
No matter how careful you are there may be some years where you will experience more dieback after you’ve pruned.  That’s just part of gardening.

Roses

For roses, look at rose canes closely.  If you see some buds swelling or even little green tips of leaves emerging it is usually feel safe to remove all canes, (rose stems), that appear to be dead, those that are brown or black and have no swelling buds. Cut back to just above a bud on a green area of cane or cane where you see swelling buds. Use sharp pruning shears and cut on a slant.

For roses that are grafted- (most tea roses and roses that aren’t sold as shrub or landscape roses), you’ll see a thickened area on the stem near the ground where the graft union is.  If there are no living stems above the graft you have probably lost that rose.  Some growth may come back from the roots, but it will be what is called rootstock and usually won’t produce pretty roses.  Roses that are grown on their own roots, however, could be cut back to the ground if all the stems above that are dead, and most will regrow from the roots to their original form.

Pruning to shape or control plants

If the goal is to simply make the plant smaller or to remove odd protruding branches then you don’t need to worry if buds are swelling, simply remove the unwanted parts.  Some plants will bleed a lot in the spring as the sap is rising.  This may not seriously harm the plant, but it may be best to prune those plants before the ground thaws and buds swell.  Maples are an example of trees that bleed a lot from pruning cuts.

Bleeding sap may not harm oaks, but it will attract oak picnic beetles, which can carry oak wilt, a deadly oak disease.  Prune oak trees before buds swell, while they are dormant.

If you prune spring blooming plants like forsythia and lilacs before they bloom you may lose a lot of the flowers because you will be cutting the flower buds off. That won’t hurt the plant, but if you want the flowers prune the plants after they bloom.

Branches that have been broken in winter storms should be neatly cut off to prevent further damage to the tree.  Use the three-cut method on larger branches- one cut on the branch underside close to the trunk about ½ way through, then cut a few inches out from that cut all the way through.  The first cut prevents the bark and wood from tearing along the trunk as the branch falls.  After it’s off trim the stump just beyond the second cut on a slant away from the trunk.  Don’t use pruning paint or sealer on the cuts.



Early spring is also a good time to cut down tree saplings that may have invaded flower beds and remove any unwanted trees and shrubs.  Some plants do better with hard pruning in the spring.  I prune my bamboo to the ground, to keep it in control.  Buddleia plants seem to do better if pruned to the ground also.  Vines like wisteria and trumpet vine, which can get out of control, can also be cut back in early spring.  You may lose flowers on wisteria in the areas you prune back.

Pruning evergreen winter dieback

After a hard winter some evergreens, usually boxwood, arborvitaes/cedar, yews and junipers may have browned or reddish areas. This is sometimes called winter burn.  Don’t be quick to prune these discolored areas off. Usually they will produce new needles/leaves that will gradually replace the browned areas.  If by mid-summer the areas show no sign that new buds are appearing, you could prune then.

Pines and spruces that show yellowed needles all along a branch may not recover needles on that branch.  Sometimes new growth will appear at the tip of the branch, however.  Wait for a while before pruning off damage.

Broad leaved evergreens like holly and euonymus may also experience winter burn.  In these cases, the dead leaves may fall off and be replaced with new if you are patient.  If they haven’t recovered by mid-summer they probably won’t recover and branches should be removed.

Pruning back the stems of smaller perennials

If you left the dead stems of perennial plants on in the fall you may want to trim them in the spring.  I like to leave a couple inches of stem. It shows me where the plants are if they haven’t begun emerging and I won’t damage them when planting or working in the garden.

Be very careful when removing dead stems from mums.  New stems emerge from the base of the old ones and they may be removed with the old if you aren’t careful to leave about 3 inches of old stem standing.  Cut, don’t pull or break off stems.

Some plants like lavender can look like they are dead, with dried leaves hanging on stems.  Yet if left alone these stems may pop out new leaf buds. This is true of semi-shrubby plants that are normally evergreen in milder climates. With these plants take a wait and see attitude.

Removing mulch, fallen leaves and so on

It’s very tempting to get out there in spring and rake those flower beds clean.  But once again patience will bring rewards.  Remove deep smothering layers of old leaves and debris but leave a light covering if you can. Dead leaves from the previous year’s growth and tree leaves that blow into beds protect the tender new growth from frosts.

I personally remove only the heaviest coverings of leaves and let the rest rot in the spring rains and enrich the soil.  In a month you won’t know they are there.  If you do succumb to the “neat” garden theory be careful when raking beds so that you don’t damage emerging plants. Some emerging foliage that has been under mulch may look yellow, but don’t worry, it will green up quickly.

If you mounded soil up around roses or other plants remove it in stages, a little at a time. If you used frames around a plant and filled them with straw or leaves, do the same, remove the coverings over a few days.  However, if it suddenly gets very warm- above 75 degrees- remove it all.  Keep something nearby to cover the exposed plants if the temperature then falls below freezing over the next few days.  That can happen here in Michigan anyway.

Burlap wraps and screens should be removed when weather is regularly above 40 degrees in spring.  Rose cones should also be removed then.

I know we are all eager to get out there and garden and it seems logical to clean up the garden and prune off dead looking stems.  But a little patience and living with “messy” conditions a little longer makes for a healthier garden later.

Making syrup from black walnut trees

In my area the maple trees are being tapped for maple syrup now.  It’s a late season, many times syrup is being made in February. The best time to make maple syrup is when days are sunny and above freezing, but nights fall below freezing.  Once leaves start appearing the syrup season is over.
Here’s something a lot of people don’t know.  While maple trees, particularly sugar maples, offer a sap high in sugar that makes distinctive tasting syrup, many other trees can be tapped for their sap and the sap made into syrup.  In Alaska they make syrup from spruce trees, in some states syrup from birch is made.  Birch syrup is made after maple syrup in some places because the sap flow starts later.

Two universities- University of Kansas and Cornell University- did some research on making syrup from black walnut trees.  A few people have been making it for years and the universities wanted to see if consumers liked it and if it could be profitable to make.  The research found that most people liked the taste of black walnut syrup; it’s lighter in color and has a slightly nutty taste along with the sweetness.  It’s a bit more time consuming to make as black walnut sap has more water than maple sap.

The same equipment and procedures that are used to make maple syrup are used to make black walnut syrup.  It’s collected at the same time too.  The bottled syrup is being offered in a few places now, but it sells for about twice the cost of maple syrup.  The two universities say there is no reason that black walnut syrup couldn’t become a profitable farm market niche product.  By the way- it’s totally safe to eat black walnut syrup. 

Plants hear bees

Can plants hear?  Researchers say yes.  Animals use vibrations in the air to hear and so do plants.  A study found that when plants “hear” the buzz of their pollinators they quickly increase the sugar level in their nectar.  This would improve the chances of a pollinator visiting and sticking around long enough to pollinate the plants flowers.  It might also make them seek out similar flowers.

Researchers at Tel-Aviv University in Israel found that flowers functioned like ears in animals, which they suggest may be why many flowers are cup shaped. When they recorded the buzz of bees and played it near flowers the plants upped the sugar content in the flower’s nectar in about 3 minutes.  Other sounds did not cause a sugar increase in nectar.

This research still needs to be replicated but it fits with all the new information we are discovering about the senses of plants.

More reading



Mushrooms might help prevent mental decline in aging

A new research study from the Department of Psychological Medicine and Department of Biochemistry at the Yong Loo Lin School of Medicine at the National University of Singapore found that seniors who ate at least two, 3/4 cup servings of cooked mushrooms per week had less mental decline with aging. (The study did not involve Alzheimer’s disease, only what is called senile dementia.)

The study involved 600 seniors over age 60 and followed them for 6 years.  Those who ate mushrooms weekly performed better on tests of cognition, depression, and anxiety than those who did not.  The mushrooms consumed were golden, oyster, shiitake and white button mushrooms, eaten fresh, dried and canned. The researchers say that they believe all mushrooms would have the same benefit.

They think a compound called ergothioneine (ET), which is an antioxidant and anti-inflammatory compound, is responsible for the effect.  People with senile dementia have less ET in their blood than people who appear to have healthy mental functioning.

Humans are unable to synthesize this compound on their own, but it can be obtained from food, particularly mushrooms.  A new study will isolate this compound and use it on participants. Other compounds in mushrooms may prevent neurodegeneration by inhibiting production of beta amyloid and phosphorylated tau, and acetylcholinesterase.

All of us older gardeners may want to add some mushrooms to our diet.  There are kits sold that will let you grow your own mushrooms too.

 More reading

Plants eat animals too

We all know there are some carnivorous plants like Venus Fly Traps, but did you know that some plants that we don’t think of as meat eaters may actually be utilizing “meat” for part of their nutrition needs? Petunias, some campions and potatoes, for example, have sticky hairs that catch small insects.  They don’t have helpful digestive chemicals like true carnivorous plants to break down these insects.  Researcher’s suspect that the dead insects fall down in the soil near the plants and break down to provide nutrition.  There may be a special group of microbes that colonize the soil near these plants and help digest the insects, and plant roots absorb the nutrients along the way.

The word “protocarnivorous” is being used to describe plants which can’t digest insects on their own, but which trap and kill insects so that microorganisms can digest them to a form that plant roots can utilize.  This behavior usually evolves in conditions where soil nutrients are low.

Shepherd's purse
Wikimedia commons

A common edible weed, shepherds purse, (Capsella bursa-pastoris) has seeds that can utilize insect meat.  The seeds exude a sticky mucilage which attracts small insects and soil nematodes. When the mucilage gets wet tiny insects and soil nematodes stick to the seeds.  They die and break down and germinating seeds use them as fertilizer.  Researchers found that seedlings which germinated from seeds that captured nematodes were stronger and had greater length and mass than seedlings that germinated from seeds that didn’t capture nematodes.

If you are one of those people who enjoy munching on shepherd’s purse salads or French fries, you may want to remember the insects and nematodes that were killed to grow the plant (or not.)

More reading

Friends multiply joy and divide grief

Kim Willis
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I write this because I love to share with other gardeners some of the things I come across in my research each week (or things I want to talk about). It keeps me engaged with people and horticulture. It’s a hobby, basically. I hope you enjoy it. If you are on my mailing list and at any time you don’t wish to receive these emails just let me know. If you or anyone you know who would like to receive a notification by email when a new blog is published have them send their email address to me.  KimWillis151@gmail.com



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