Garden Plot: Perfect time to plant a good lawn

WASHINGTON – This is the time to take a bad yard and turn it into the yard you want.

Jessica in Ashburn writes, “We just moved into a new house with a big, bad yard. The lawn is patchy and covered in weeds. I know this is prime time for lawn care, but I have no idea where to start! I am so confused about weeding, seeding and feeding and I need to know how to do it all without poisons. Please help!”

My pleasure, Jess! This is the perfect time to start over and poisons are never necessary. In fact, the more of that junk people use, the worse their lawns tend to look.

Till up what is out there, rake away as much of the old green material as possible, level it out, have a big load of compost or high quality topsoil delivered and spread it an inch deep overtop of the cleared area. Then level it again. It’s an important step that many people neglect. Leveling is crucial to long-term lawn success. Then, sow a high quality, name brand seed (turf-type tall fescue is the easiest type of cool-season grass to care for), rake it into that nice rich seedbed and water gently twice a day until the new grass comes up. Do not cover it with straw or other ill-advised nonsense.

Grass seed sown between Aug. 15 and the end of September will thrive and your new lawn with soon look great. For long-term care, never cut the grass below 3 inches, cut it with a mulching mower that returns the pulverized clippings to the turf, feed it every spring and fall with corn gluten or compost, and if you need to water do so deeply for several hours and infrequently, never more than twice a week. Short, frequent watering equals weed-filled lawns.

Aerating a lawn in spring means 75 percent weeds

Shirley in Gainesville writes, “Our lawn was once hardy and pretty much weed free. Over the past decade, we had it aerated three times, with the most recent aeration being done in spring 2011. We also over-seeded then as it was looking weak. Unfortunately, we now have a yard that is 75 percent weeds! Where do we find the weed-killing corn gluten that you talked about on the radio recently?”

Sorry, Shirley, all that corn gluten can do is feed the grass and prevent new weed seeds from germinating. It can’t magically dissolve existing weeds. When a lawn is more than half weeds, it should be torn up and a new lawn planted. Luckily, anytime over the next month is the perfect time to do so.

And unfortunately, your timing up to now has caused much of your current problem. You should never aerate or seed cool season lawns like bluegrass and fescue in the spring. Aerating in the spring is especially bad. The correct time to core aerate a lawn to relieve compacted soil is during the month of September, when the cool season grass can quickly recover from the shock of all those plugs being removed. Aerating in the spring (or even worse, in the summer) severely damages cool season lawns.

Bad bloom on hydrangeas

Michelle in Silver Spring writes, “I have three different types of hydrangeas in my backyard, but only one blooms (the white one). I get sun through the trees … it’s not complete shade. Can you advice what I should do and why?”

There are two main reasons for lack of bloom on hydrangeas, Michelle. The most common is improper pruning. Hydrangeas should only be pruned to remove non- flowering branches, and only after the current year’s flowerheads have all bloomed in late spring. Pruning them at any other time of year can cut off flower buds.

The other big cause is lack of sun, and I suspect that’s at least part of your problem. Most hydrangeas require full sun or at least half a day of full sun to bloom well. Your white bloomer may be an oak leaf hydrangea, which tolerates shade better than the other types. Bottom line, if you’ve been pruning without a plan, stop. Otherwise, think about moving the plants to a sunnier spot. September through November would be the ideal time to do so.

The tomato hornworm: A hungry, hungry caterpillar!

Bill in Manassas writes, “My tomato garden is being invaded by some sort of worm or caterpillar critter eating the tomatoes. How do I get rid of them?”

That would be the tomato hornworm, Bill, and despite its unfortunate common name, it is a caterpillar. In fact, any plant pest whose common name ends in worm is actually a caterpillar.

Hornworms are among the biggest caterpillars in North America, eat lots of plant material very quickly and blend in almost perfectly with the plants they’re eating. They blend so perfectly in fact that the best way to find them is to first spot the big piles of frass (a $20 word for bug poop) underneath their hiding place and then follow the trail up.

Then you can handpick and squish them. Unless they have little white spines down their back, if that’s the case, take them off the plant but don’t kill them. Those spines are actually cocoons that will produce tiny wasps, so small we can barely see them, that parasitize pest caterpillars. So when your tomatoes are under attack by a big caterpillar with some egg cases on its back, take it away from your plants, give it some damaged tomato branches to feed on, and it will incubate hundreds of little wasps that will prevent further caterpillar problems.

The Pesky caterpillar that becomes a beautiful butterfly!

Maureen in Annapolis writes, “This weekend we saw these bugs in our garden on the cilantro. Are they some particular type of caterpillar? They’ve almost entirely eaten the plants!”

The photo that Maureen attached, which you can see above, unmistakably shows the very distinctive parsley worm, an attractive striped yellowish caterpillar that morphs into one of our most beautiful butterflies, the parsley swallowtail.

The vast majority of caterpillars that eat farm and garden crops grow up to be ugly little night flying moths. But, when the caterpillar is eating parsley, cilantro, dill, carrots or other members of those plant families, the butterfly is beautiful. You can handpick the caterpillars if you wish, but most butterfly lovers just plant extras of those crops and enjoy the show.

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