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Tips and Tricks from County Master Gardeners Archived Discussion Room

Fairfax County, Virginia

Tips and Tricks from County Master Gardeners

Did you know that Fairfax County has a robust volunteer Master Gardeners program? Now is prime time for planning and planting, and Master Gardeners John Meenan and Sunny Greene are here to help. Join them online Wednesday, May 4 at 11 a.m. to learn more about the program, how to become a volunteer and how to find gardening success with your own plot of land in the county.

Pamela Smith : Good Morning!
    Welcome to this forum. John Meenan and Sunny Greene of the Green Spring Master Gardeners and Gill Medeiros of the Fairfax County Master Gardener Association are here to answer your gardening questions. I am Pam Smith, also with the Green Spring Master Gardeners. Let's have fun today because it's gardening season in Fairfax County!

Joe : Which native plants are best for ground cover in a heavily shaded area? In addition to ground cover I would like to prevent erosion.

Pamela Smith : We also need to know if the site is moist soil or dry. Since you can't ask that, we will give you some options. We recommend native pachysandra which will grow in either moist or dry soil. It is not as vigorous as the non-native pachysandra but be patient and it will do well. Carex plantaginea, seersucker sedge, is another option, however, not in extreme dry or wet soil. Crysogonum virginianum is another native (Green and Gold), however it is evergreen in mild winters. Ferns are also another great option - Christmas fern, Polystichum acrostichoides. The Virginia Cooperative Extension (VCE) puts out a publication on Ground Covers #426-609. Go to

Dawn : SLUGS! We have a whole colony taking up residence in my gardens. Eating my hosta and coneflowers, chewing on the annuls What's the best method for banishing them without poisoning our pets? My potted annuals are getting hit especially hard. Thanks!

Pamela Smith : A good organic method is to get diatomaceous earth at local garden centers and spread around the garden area. It will not affect the plants or animals. There are commercial baits that contain iron phosphate which attract slugs. It is approved by the Organic Materials Research Institute for use in organic gardening. Otherwise, if you are not squeamish, pick them up and throw them in a bucket of water.

Laura H. : Help! I have a ton of dandelions in my back yard. My husband doesn't want to add any chemicals because he says it hurts the Chesapeake watershed and our kids play back there. But my next door neighbor is mad because they are going in to his yard. Any suggestions?

Pamela Smith : Dandelions are a non-native scurge! The only organic way to get rid of them is good old fashioned digging them up. Give the kids some tools and go at it! Use a long pronged tool that you can obtain from a garden center and dig deep enough to remove the tap root.

Anonymous User : I live in a third floor apartment with a balcony that gets a good amount of sun. I'm interested in growing a few vegetables plants and starting with tomatoes because I've heard their easy to grow. What should be my first steps to growing a tomato plant on my balcony? Should I buy a plant or seeds and where should I buy them? What type of soil should I buy? Thank you!

Pamela Smith : First, be sure that your balcony can hold the weight of a heavy pot with soil. Second, the container should be big enough to grow tomatoes, about 15" or 5 gallons capacity per plant. Use soilless potting mix. You can add compost to it for the nutrients. Do not use garden soil! It is too heavy and can contain diseases. Tomatoes need to be babied! add a cup of ground limestone in the mix. You will need added fertilizer eventually so we would suggest Osmocote. Next, choose a seedling over seeds. It is somewhat late to start from seed. It is best to use a determinate tomato plant. It will stop growing as soon as it starts to set fruit. Patio tomatoes are smaller plants but it depends on the type of tomato you like. We find the cherry tomatoes to work best in a container. Use a tomato cage with netting to keep the tomato hornworm off your tomatoes as well as hungry birds. Keep evenly moist, watering every day. Pots dry out very quickly. Go to for publications #426-336 Vegetable Gardening in Containers and #426-418 Tomatoes.

Rich : What is the best way to get rid of spider mites on my fruit trees?

Pamela Smith : First, are you sure they are spider mites? Bring in a specimen to your local Master Gardener plant clinic, at local Fairfax County Farmers Markets or local libraries. For an organic method, use a miticide, M-Pede(2% solution) and for further advice, do not apply miticides on a preventative basis - meaning only when you see the mites. This miticide only kills on contact. More information can be obtained from the Virginia Fruit website, www.Virginia

Anonymous User : Tulip maintenance! I've cut off the crowns of my spent tulips. When can I remove the leaves so it's just the bulb in the ground for next fall? Thank you!

Pamela Smith :  You need to wait until the leaves turn yellow and dieback. All the nutrients for the coming year are contained in those leaves. Just know that most tulip varieties are not reliably perennial in this area, so don't be discouraged if they do not come back next year. Plant more in the fall, just in case.

Anonymous User : What do you recommend to address the problem of powdery mildew, especially on tall phlox? It seems to have started early this year. The plants are not crowded and get at least 6 hours of sunshine (when it's not raining like it has been lately). Thank you.

Pamela Smith : The most important advice is to choose phlox that are more resistant to powdery mildew. Check the label before purchasing. For a chemical control for the phlox you have now, use organic commercial products containing several of these fungicides which are OMRI-approved, e.g. neem oil, potassium bicarbonate and sulfur. A non organic product that you could use would contain chlorothalonil. The reason the powdery mildew started early is due to all the rain and resulting dampness that we have had over the last month. We need more sun!

Marcus : My boxwoods are showing some brown, dead leaves in various places. I have about 12 boxwoods. There's a lot of new growth, so are the brown leaves just passing on? Should I remove the brown leaves? It seems like whenever I trim boxwoods, the tops either turn brown or white. Am I doing something wrong?

Pamela Smith : The best advice we can give is to bring in a specimen to a Master Gardener plant clinic. It could be boxwood blight. Clinics can be found at Green Spring Gardens on Saturdays, or Farmers Markets throughout the county. Also, to address the trimming, you need to get air and sun into the middle of the plant. Don't just shear the outer edges but do thinning cuts on the interior branches.

Anonymous User : Tulip followup: Thanks for answering my question and the advice on planting more. When planting more, what if disturb any existing bulbs in the ground? Can I move them around? Plant a fresh bulb next to an older bulb? Thanks!

Pamela Smith : Yes! you can move the existing bulbs as you wish. Placing a young, fresh bulb is not a problem just don't crowd them. Check the spacing on the label.

Clueless Gardener : Colorful, 6-10" continuous bloom perennials? Trying to find a flowering perennial that can be used for ground cover of a fairly large garden bed in a pretty sunny spot.

Pamela Smith : Perennials are not continuous bloomers. That is left to annuals. However, dwarf daylilies will bloom profusely in June, then a little less in September and then a little bit more in October. They love the sun.

Ashley : I just planted my raised bed over the weekend. I have a few marigolds nearby, but I'd like to add a pot of pollinator-friendly flowers. What would you suggest? Could I buy any pre-made flower pot at a local store -- will that suffice?

Pamela Smith : Is your raised bed for vegetables? If so, the marigolds will not attract pollinators but they will help keep some of the harmful insects away. Bumblebees are the best pollinators for vegetable plants. Plant zinnias, cosmos, lantana, salvia, snap dragons, sunflower and lavender which will attract these excellent pollinators and others. Try planting these flowers in several pots around the raised beds or even dedicate a section of the raised beds to these plants. Some are even edible!

Anonymous User : Last year I planted kale and spinach that turned out to be quite bitter. What are some tips for making sure that doesn't happen this year? Any thing I should be doing to the soil?

Pamela Smith : It is best to harvest these crops when it is cool outside and before they produce flower stalks. When the plant starts to produce seed, it withdraws sugar from the leaves thus producing a more bitter plant.

Anonymous User : I have a yard that's about 15-20 yards long. The bottom half of the yard is unusually wet and always wet after it rains or after I water my vegetable garden, which is located there. In the winter, the area is often soggy. However, the other half of the length of this area is just fine. Is this something I should be worried about?

Pamela Smith : This is a tough question to answer. We would need more information about your yard, the steepness of the slope, the type of soil, runoff from other parts of the yard, etc. You may need help with improving drainage in that part of the yard or as an alternative, consider planting a rain garden. Vegetable plants don't generally like to have wet "feet". Try raised beds for better drainage.

Pamela Smith : Thank you for joining us today. We had a great time answering your questions. Join us at the Master Gardener Plant Clinics at Fairfax County Farmers Markets or Saturdays at Green Spring Gardens Help Desk. You can call the Virginia Cooperative Extension Help Desk at 703-324-8556 Monday through Friday, 9:30 am - 12:30 pm or for more answers to your gardening questions.