In case you missed my lunchtime chat on springtime gardening, here's what came up:

MODERATOR: We're starting the live chat with Jessica Damiano now. I'll be posting gardening advice throughout the chat as she writes responses to your questions.
   
GUEST: What are the chances that my potatoes will get late blight again this year?

JESSICA DAMIANO:
Hi, Guest. I'm glad you asked. While late blight, a disease caused by a pathogen that ravaged Long Island potato (and tomato) plants last summer, cannot survive in our climate in dead plant tissue or soil, it CAN survive in live plant tissue, like potato tubers. So if you still have any tubers in the garden, dig them up and discard them right away. This is especially important if you suspect your plants were infected by the disease last year. I heard from Cornell plant pathologist Meg McGrath last week about this very subject. She's concerned that if plants sprout from tubers that were left in the ground over the winter, they may develop late blight and become the source of another epidemic in the Northeast. And ditto for the compost pile. If you composted any infected (or even possibly infected) potatoes last year, better to discard compost than take a chance. There's not much of a worry for tomatoes because, again, the disease wouldn't survive in soil or dead plant tissue.

PC: Hello, not sure if this is part of the subject matter. I have Rose of Sharons along my fence line. I'd like to put another bush/tree-type plant in between them since the Rose of Sharons bloom so late. I was thinking Forsythias. Any ideas? Thanks!

JESSICA DAMIANO: Hi, PC. You could go with Forsythia, but if you're looking for a spring-blooming shrub, you also might consider interplanting your Rose of Sharons with Rhododendrons, which are just getting ready to bloom now, April-blooming flowering quince, or lilacs, which should bloom in about a month. Each will bloom for two or three weeks. To extend the color, you can plant catmint (I love Nepeta 'Walkers Low'), which will bloom purple from late spring through frost, or lavender. And don't rule out underplanting the shrubs with spring-flowering bulbs and/or perennials like Phlox 'David', which is white and would complement your Rose of Sharons nicely.
   
SEAN: When does sod become available for purchase from the large box stores in our area?

JESSICA DAMIANO: Hi, Sean. You can pretty much install sod at any time of year (even in winter, believe it or not), but the best time to do so would be in September, when cooler temperatures are ideal for getting it established and it will require less watering. Spring is the next best time, so you certainly can sod the lawn successfully right now. Plus, you'll get the advantage of all those April showers to help it get established. I'm not exactly sure when the big box stores in our area start stocking sod, but I would imagine very shortly.
   
MODERATOR: You heard it here first: This year's Great Long Island Tomato Challenge will be held on Friday, Aug. 27 at 7 p.m. Last year, more than 100 readers competed in the quest for Long Island's biggest tomato. Keep Jessica posted on your progress by sending details and photos of your garden and plants to jessica.damiano@newsday.com.
   
LAURIE CONNORS: When can you separate either Shasta Daisy's or Black-eyed Suzys?

JESSICA DAMIANO: Hi, Laurie. The basic rule of thumb for perennials is to divide (or transplant) spring bloomers in fall and fall-bloomers in the spring. So, to answer your question, shasta daisies can be divided now. Black-eyed Susans are pretty tough and tolerate division very well. It's ideal, though, to separate them while they're still dormant in early spring or in late fall.
   
MODERATOR: Here's an inside tip for contestants vying for the biggest tomato: Plants with the biggest fruit potential include Radiator Charlie’s Mortgage Lifter, The Dutchman, Big Zac, and any of the giant Belgium or red Beefsteaks.
   
Past winners of the Great Long Island Tomato Challenge include a 4-pound, 9-ounce Burpee Porterhouse (currently the title holder and largest Long Island tomato on record) a 3-pound, 1-ounce Bull's Heart and a 3-pound, 14-ounce "Ugly" tomato, grown from Italian seeds.

PETER: My weeping cherry decided to bloom yesterday -- an event I look forward to almost as much as the Mets' opening day. A lot of people prune their weeping cherry trees from the top, keeping them small and dense. I've let mine go, well above the roof of my house. Other than it being less dense, will this cause anything bad to happen?

JESSICA DAMIANO:
Hi, Peter. Weeping cherries generally don't need much pruning, but (especially since yours is over your house) it's important to remove any dead, damaged or diseased wood once a year, right after it blooms. Also, remove any water sprouts or suckers that grow. Avoid pruning the tips, even if they reach the ground. That would give the tree an unnatural appearance. Just be sure to apply mulch around the tree under the trailing branches.
   
GARDEN CHALLENGE: Hi, What's the best way to organize a garden? Should it be separated in 4 x 4 areas, or just keep it in lines as in one space?
   
JESSICA DAMIANO: Hi, Garden Challenge. If you're asking about a vegetable garden, you have a few options: You can go with raised beds, squares, mounded hills or simple rows. The important thing is to account for the plants' mature size when planting seedlings or starter plants. Space tomatoes 2-3 feet apart in rows 4-5 feet apart, for instance. That might seem excessive when you're planting 6-inch tall plants, but it's necessary so that, come August, you'll be able to get around plants to weed and harvest. Plus, proper spacing allows for sunlight to reach all parts of the plants and allows for the necessary air circulation, which cuts down on mildew, mold and fungal diseases.
   
MODERATOR: Whether you're new to gardening or are an old pro, here are 8 gardening trends, which will help you plant for flavor, beauty and ease: http://www.newsday.com/lifestyle/home-and-garden/8-gardening-trends-for-2010-1.1840551

CHRISTINE: When is the best time to cut back dead wood on hydrangeas and how should it be done?
   
JESSICA DAMIANO: Hi, Christine. That all depends on what type of hydrangea you have.

Hydrangea macrophylla, should be pruned in late summer, as soon as the flowers fade, but never after September. Remove weaker stems from the base of the plant, being careful to retain several stems of old wood, which will produce buds for next year's flowers.

Hydrangea arborescens Grandiflora should be cut to the ground in late winter/ early spring.

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For Hydrangea paniculata Grandiflora (Peegee), simply remove spent flowers and thin or cut back last year's growth in late winter/ early spring.

For Hydrangea quercifolia (oakleaf hydrangea), remove dead wood at the base of the plant in early spring.

Hydrangea anomala petiolaris (climbing hydrangea) seldom, if ever, need to be pruned at all. But you can shorten unruly vines in summer.

If you're not sure which hydrangea species, you have, compare it to these photos: http://www.newsday.com/lifestyle/home-and-garden/which-hydrangea-is-yours-1.1436967

FRESHVEGGIES: When is the best time to plant a vegetable garden?

JOHN: Is it too early to plant my vegetable plants?

JESSICA DAMIANO: Hi, FreshVeggies and John. The answer depends on what type of vegetables you'd like to plant. Peas, for instance, can be planted directly in the garden now. Cole crops (cabbage, kale, lettuce, cauliflower and broccoli) can be set out in the garden by the end of the month. But it's way too early for other vegetables, like tomatoes, eggplants, peppers, zucchini, cucumbers, etc.

FRESHVEGGIES: OK, when can we plant the "other" veggies?

JESSICA DAMIANO: For those, you'll have to wait until after the danger of frost has passed, which is in the middle of May. I always wait until Memorial Day weekend, just to be safe. Last year, we had an overnight frost on May 11, and several people I heard from lost tomato plants. In fact, I had been hardening off my seedlings and I forgot to bring them in that night. They all died and I had to start over. Resist temptation to plant vegetables or even annuals this week, even though the weather is very summer-like. Wait until the end of May.
   
FRESHVEGGIES: Thanks

JESSICA DAMIANO: My pleasure :)

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AD: Hi! Just wondering when I should put down Scotts Step one fertilizer with HALTs crab grass preventer?

JESSICA DAMIANO: Hi, AD. Actually, those combo products shouldn't be used. Right now is the best time to apply pre-emergent crabgrass control, but it's the wrong time to fertilize. So go ahead and use a crab-grass prevention product now (give corn gluten meal a try; it's all-natural), and then fertilize at the end of May.

Most residential lawns require 2 to 3 pounds of nitrogen per 1,000 square feet per year, which should be divided up into three separate applications. Fertilize around Memorial Day, July 4th and Labor Day. In the past, a 4th application around Thanksgiving was recommended, but that advice is outdated and, in fact, even illegal now on Long Island because of groundwater pollution issues.

In Nassau, it is illegal to apply nitrogen between Nov. 15 and April 1; in Suffolk, the banned dates are between Nov. 1 and April 1. The new rules also are cost effective for homeowners because grass likely wouldn't use up nitrogen applied late in the growing season, anyway, so not only would the excess nitrogen run off and pollute the water table, it would be a waste of time and money, as well.

GARDEN CHALLENGE: Thanks for the advice

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CITYDWELLER: Any tips for those of us who live in NYC apartments? What grows well in windowboxes? Should we put them out now, or wait?

JESSICA DAMIANO:
Hi, Citydweller. Are you talking about vegetables or flowering plants?
   
STUCK IN THE SHADE: My entire backyard is home to trees and the majority of the space in the back is shade as a result. What flowering plants would you recommend for the back?
   
MODERATOR: As Jessica is answering, take a look at 5 ways to spruce up your lawn: http://www.newsday.com/lifestyle/home-and-garden/how-to-spruce-up-your-lawn-1.222115

MODERATOR: And, also take a look at the 6 items Jessica wouldn't garden without: http://www.newsday.com/lifestyle/home-and-garden/6-items-i-wouldn-t-garden-without-1.1219862

   
JESSICA DAMIANO: Hi, Stuck in the Shade. There are lots of plants that will thrive in the shade. If your shade is caused by deciduous trees (those that lose their leaves in autumn) like dogwoods, maples or oaks, then it's only an issue when the tree has leaves. You can take advantage of the sun exposure you get before the tree leafs out and grow some sun-loving early-season bulb plants. Try crocuses, tulips and daffodils to brighten the spot. As far as annuals go, Impatiens do really well in the shade. Hellebores bloom in the shade, in fact, they're blooming right now. And I also like Ligularia dentata (leopard plant) "Britt-Marie Crawford," which has striking large deep-purple leaves and yellow daisylike flowers in summer. It requires a lot of water, though, or it wilts. And I love Tradescantia 'Sweet Kate' (spiderlily). It has bright chartreuse grasslike foliage and small purple flowers. Dicentra spectabilis (bleeding heart) blooms from April to May, and Actaea 'Hillside Black Beauty' (baneberry) has cream flowers that seem to float above deep purple foliage in late summer and early autumn. Astilbes are a shade no-brainer, and they come in white, pink and red. Also consider Pulmonaria (lungwort) and Tiarella cordifolia (heartleaf foamflower), which bloom in spring.

MODERATOR: In reference to the question about what to plant in window boxes...

CITYDWELLER: Either flowers or veggies.... not sure what works
   
STUCK IN THE SHADE: Thank you for all of your help

JESSICA DAMIANO:
Hi, Citydweller. You can plant both in window boxes -- in fact, you can combine both in the same window box. Try surrounding pansies with red- and green-leaf lettuces. You also can plant cherry tomatoes in window boxes, and all kinds of herbs. If you have shallow boxes and want to grow edibles, try onions, lettuces, spinach and chards. If you want to plant broccoli, tomatoes, carrots, peppers or eggplants, go with a container that's 12-14 inches deep. Beans, cucumbers, squashes and potatoes require deeper containers, like 18 inches.
   
MODERATOR: We're posting the last question now. Jessica will reply to all other questions in upcoming blog posts on Garden Detective (newsday.com/gardendetective)
   
GREAPOR: When would be the best time to prune my leyland cypruses?

JESSICA DAMIANO: Hi, GReapor. Prune your Leyland cypresses now. Take care to clip each individual branch -- never shear them!

MODERATOR: Thanks everyone! Be sure to upload photos of your spring blooms: newsday.com/springblooms

GREAPOR: Thank you
   
JESSICA DAMIANO: Thanks for visiting, everyone. Sorry if you posted a question that wasn't answered. I'll get to unanswered questions as soon as possible on my blog, newsday.com/gardendetective, so stay tuned. Happy spring!