Tuesday, August 4, 2009

August Gardening Chores

Reclaiming your garden. Weeding is a perennial chore (pun intended) but this year weeds seem to have thrived more than usual. I blame the rain, but whatever the reason, the weeds are taking over and have buried half of my perennial garden. The half, which seemed to be doing the best this year are part shade plants which were not overwhelmed by all the rain and lack of sun this summer. For instance Daylilies (Hemerocallis), False Dragon’s Head (Physostegia) and Fall blooming Windflower (Anemone) have bloomed quite vigorously this year and spread. So this fall will be a wonderful time to divide those plants, and maybe share some with friends or neighbors.

Powdery mildew has been a real problem this summer with the rain and high humidity, this

fungi looks like baby powder coating leaves of perennials, shrubs and even trees. The fungus can be treated with a fungicide or even a simple solution of baking soda. Also, make sure that

there is plenty of air circulation around the plant. If your Monarda, Roses, Paeonias and Phlox (etc.) are infected, thin out the plants and dispose of the infected leaves (not in your compost!) as the fungus can over winter.

Bulb catalogues are starting to fill up mailboxes. Before you place your order, find those pictures of your spring garden and determine which bulbs are ready to be divided or moved and then select your additional plants. Keep in mind that bulb planting shouldn’t start before October. You can get some great discounts by ordering early and responsible companies won’t ship them until proper planting time. But for the others, be sure you have a cool, dry place to store your bulbs until you can plant them.

Consider keeping your lawns longer, mow at 2 1/2” to 3”. The UMass Turf department reminds us that longer blades of grass directly correlate to deeper roots (and deeper roots need less frequent watering).

Thank you to everyone who has sent in ‘Questions for Cory’. I will try my best to answer those questions here.

Q. I would love to see you post some advice, and or pics of pruning a lilac. I have one that is 8 feet high, gangly and in need of a severe pruning.

A. This is such a great question, and Common Lilac (Syringa vulgaris)

does get gangly and top heavy and a healthy plant can rebound quickly from very aggressive pruning. So don’t be shy.

Here is how I typically approach rejuvenating or “hard pruning” Lilacs: start by taking out the oldest wood, the gnarly, desiccated branches in which insects are probably making homes. If they have open cavities, signs of borer insects or breaks then prune them all the way to the ground, if they are relatively healthy, then hard prune them leaving 18” from ground to top of branch.

Step back and look at the shrub, and surrounding area. Chances are the growth is at the top third of the plant, and the plant is probably 3’ taller than you want it to be. Which means that you will be removing 90% of the foliage to bring the shrub down to the height you want. For a Common Lilac (Syringa vulgaris), this is OK. Next step, I take out about half of the main branches, so if you have 12 main branches to your shrub, pick the 6 oldest, weakest, or most poorly shaped and prune them to the ground. Leaving 6 strong, straight and healthy branches. Then, if you want your ultimate shrub height to be 5’, prune your remaining branches to 4’ tall (1’ less than desired height). This picture shows a Lilac 4 weeks after we pruned as described above. Notice all the healthy, new growth at the base of the plant. This new growth will continue to grow and "fill in" the skeletal area framed by the old branches left behind.

There are lots of other methods and approaches to pruning Common Lilacs (Syringa vulgaris). And healthy Lilacs will tolerate almost anything, so feel (to use my daughters new favorite word) empowered and go for it. This method is not the same you would use for other shrubs or other species of Lilac, like Meyer Lilacs (Syringa meyer “Miss Kim”) or other small leaved Lilacs, which have a different growth habit and often a single main stem.

The best time to prune Lilacs is early June, after the blooms have faded. But if you missed the window and can’t wait until next year, just be sure to fertilize your shrubs after pruning, and water regularly for the next two months. And keep in mind that Lilacs (like other European plants) benefit from annual liming.

And my last note on Lilacs, I have seen scale (Peach scale?) and aphids on a lot more Lilacs this year. And scale is a nightmare to get rid of, so be sure to clean your tools between pruning jobs, especially if sharing with neighbors. It will help slow the spread of some of these insects.

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