Monday, May 9, 2011

May Garden Chores

May means flowers to me, and this May has been rewarding so far. With Lilacs (Syringa sp), Dogwoods (Cornus florida) and Crabapple Trees (Malus sp) in full bloom all over town, winter is just a fuzzy memory. For anyone who can’t get enough of Lilacs, the Arnold Arboretum has an incredible array of different Lilac cultivars and species in bloom right now, from the Common Lilac (Syringa vulgaris), to Hybrid Lilacs (Syringa x chinensis) and Meyer Lilacs (Syringa x meyeri) stop by for a sweet sniff or visit their website for more information.
Things grow and change quickly in May so here is a list of gardening chores and tips to help keep you on track:
Malus "Sugar Tyme"
The Wintermoth caterpillar is active again, and munching away at the leaves of Maples, Crabapples, Cherries and other trees. This destructive little green caterpillar, which looks very much like an inchworm, can defoliate your trees in a very short period of time.  If you suspect your trees are infested or you had trouble with them last year, contact your arborist or landscape professional for assistance. There are organic treatments to control this non-native pest.
Fertilize bulbs blooming right now with 5-10-5 or similar fertilizer if you are planning to perennialize them (get them to bloom next year).  Work about a teaspoon into the top of the soil around each clump.  And leave the leaves; they are still gathering energy for next year’s blooms.  Some bulbs like Tulips are often treated as annuals because of the pests, diseases and level of care needed to effectively perennialize them.
If you haven’t fertilized your lawn yet, now is a great time (May, September and November are the best times).  Use a spring fertilizer or one with a ratio of 4-1-2 or 3-1-2 (nitrogen, phosphorous and potassium). And leaving the lawn clippings on the grass after you mow also helps to return nitrogen to the soil.
Now is also the time to sow your annual flower seeds and vegetable seeds such as eggplants, peppers, potatoes and tomatoes.   Plant these seeds directly in the soil.  It is also very easy to grow many herbs and veggies in pots on a Deck or in a Patio space.  This close proximity to the house can make it easier to monitor their watering and possible attack from bunnies and other pests.
Prune back the winter damaged leaves and branches allowing for more sunlight and air circulation for the new growth to thrive.  I have seen quite a bit of “Sunburn” damage this year, especially to Rhododendrons, which may have gotten too much sun from the reflective snow cover this past winter. But by now you should see new buds and new growth on the plants, which is a sign that they will bounce back. The exception is of course plants in deep shade, which may need another week or two to show signs of life; and our garden teenagers who “sleep until noon” meaning they may not leaf out until late May (Clethra, Itea and Hostas to name a few).
Be careful to dump out rainwater collecting in accidental places, remember that mosquitoes can develop in standing water that remains for more than 3 days.
Remove stakes, tree wraps and guy wires from trees planted last fall.  They can pose long-term problems for trees if left on too long.
To help in your selection of a new or replacement tree, visit the Arnold Arboretum or Mt. Auburn Cemetery.  Both locations accurately label their plant material and seeing trees, as mature specimens and seeing them ‘off-season’ will help you make an informed decision.
Thank you to everyone who has sent in ‘Questions for Cory’, keep those great questions coming.  I will try my best to answer those questions here.

Q. Last week I removed the winter mulch from my perennial garden as things were slowly starting to grow. And this week it is full of weeds! What happened?
A. Suddenly spring! In the past 2 weeks our Growing-Degree-Days (GDD – which is the internal clock for many plants) has doubled and triggered a lot of activity in the plant world, seemingly all at once. Unfortunately, this includes weeds. If you can’t get to weeding all areas your garden this week, then I recommend focusing on those which are flowering right now such as Dandelions, creeping Veronica, Chickweed and Garlic-Mustard a biennial plant and prolific seeder. Otherwise, those weed flowers will turn into weed seeds and those weeds will spread. And remember the old garden adage – “One year of weed, equals seven of seed.” Guess I’d better finish this up and get to weeding myself!

Monday, May 2, 2011


Volcano mulching is the nic-name for the VERY BAD practice of installing mulch literally up the trunks of trees thereby creating what looks like a “Volcano” of mulch from which the tree trunk is erupting. (see below for a partial list of reasons WHY this is BAD).
An example of "Volcano Mulching" - a VERY BAD practice.

There are many reasons why "Volcano Mulching" is detrimental to the long term health of the tree, here are a few:
  1. Trunk Rot - Bark tissue is different from root tissue and not "designed" to be continually moist or submerged. Covering the trunk with mulch will keep the bark moist and eventually the bark will decay, this will further lead to insects and disease feeding on the decayed tissue and eventually the tree (or shrub) will die.
  2. Suffocate/ Girdle the tree – Tree roots collect oxygen for the tree, the surface roots are now smothered by too much mulch so the distressed tree will send out little capillary roots into the mulch. Unfortunately these little roots are now above the soil line and subject to summer heat and winter frost damage and if they manage to survive these afflictions the roots grow larger encircling the thee trunk and eventually girdling or choking itself.
  3. Thirsty Tree - In the image above the slope is pushing water away from the tree before it has a chance to absorb into the ground. And the mulch is so thick, it is highly unlikely that rainwater could penetrate that mound and reach the tree roots where the water is needed.
  4. Home for pests – Mice, voles, insects etc. now have a comfortable home right next to your tree trunk and they can feast away undetected. Poor tree!

 Did I mention that this is a BAD practice?
Proper application of mulch can be helpful, especially when establishing new plants:
Keep Soil Cooler in heat of summer
Reduce water evaporation
Reduce soil erosion from wind (and water runoff)
Proper application of mulch should not submerge the tree flange let alone cover the bark. And it should not be deeper than 2" to 4" (at the most!).