May Gardening Chores

The blooms of Crabapple Trees (Malus sp) and Lilacs (Syringa vulgaris) have been particularly glorious this year, and we have so many beautiful specimen all around Dedham, congratulations to everyone who has worked so hard to keep them looking healthy. Mother’s Day is Sunday, remember Mom with a lovely blooming shrub or tree. Lilac Sunday at the Arnold Arboretum is May 9th, call or visit their website www.arboretum.harvard.edu for more information.

Our early spring may have thrown your gardening calendar out of whack, so here is a list of May gardening chores and tips to help you out:
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.
Also I have started to see signs of Winter moth caterpillar this spring, this is the little green insect which looks very much like an inchworm and they may be eating the leaves of your Maple, Oak, Crabapple, Cherry and other trees. If you suspect your trees are infested or you had trouble last year contact your arborist or landscape professional for assistance. There are organic treatments to control this non-native pest.
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.
Move your houseplants outside when evenings become reliably warmer. Remember they need to be acclimated; if you move a plant from the house to a full sun area chances are it will burn. Try moving them first to a shady spot in your yard and bring them out gradually. I put my houseplants under a big old Rhododendron, and I leave my Christmas cacti there until October.
And last but not least - Weed, weed, weed your garden. ‘One year of weed equals seven of seed’ if you let those annual weeds grow and set seeds you will be haunted by their offspring for years to come. Many annual weed seeds can remain dormant for years just waiting for the right time to come back and haunt you.

Q. I recall lilacs (Syringa vulgaris) blooming around here about first or second week of May each year. I wonder if late April is unusually early, and if so what could be the cause?
A. Good question, and yes many plants are blooming “earlier” this year, and you may see some non-typical crossovers (plants blooming simultaneously which don’t normally bloom simultaneously). Bloom times are not clock work, estimated bloom times are based on averages, but this spring is “early”. As for “the cause” I won’t speculate on climate change as that is not my area of expertise, but I will say that soil temperature triggers many plants to start growing. More precisely described it is the accumulated warm soil temperature days, commonly referred to as Growing-Degree-Days (GDD), this year we have had 138 GDD since the first of the year. This is very high. UMass Amherst tracks GDD for most of Massachusetts, and I checked their archives and found that at this time last year we had 87 GDD but in 2008 we had 111 GDD. So, what does this mean for your Common Lilacs? They are fine with the variation in bloom schedule, as long as the winters don’t go below -25’ F and the summers don’t turn into southern Florida.