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Posted at 1:15 PM ET, 03/10/2011

Spring into action, gardeners!

By David Streit

Early spring planting tips from a gardening meteorologist...

Average temperatures over the last month. Source: High Plains Regional Climate Center

Notwithstanding the current and recent deluges, planting time is fast approaching. I always like to keep an eye on the map of average temperatures over the past several weeks (shown to the right). It is a good rule of thumb for monitoring soil temperatures in the garden. As you can see, we have risen above the 40 degree mark and that signals the beginning of plant awakening in our area.

Most seeds need a certain minimum temperature for germination and this is a great guide for planting. As some of you have already shared, your early bulbs are already off and blooming with many more about to explode into masses of color. Isn't it great to see! For those of us who struggle to get motivated about planting bulbs in the fall, now is payoff time. We will talk a lot more about bulbs in the fall as I encourage you to take advantage of a great early highlight in the garden.

This is a great time to get cool season veggies sown, like lettuces, if you have a plot or even just a pot. Temperatures around here climb pretty quickly this time of year so you have to move fast to take advantage of this window. If you are working in the garden, it is a good idea to wait at least three and preferably five days to work the soil after a rain like we are having. This is especially true if you have clay soil like most of us do. Work it too early after a rain and it will turn into a brick that very little will emerge from. Timing is going to get a little tricky as we are coming into a wetter period right now, so use our daily Capital Weather Gang forecast to plan ahead. The good aspect of the wetter weather is that the moisture deficits look likely to be a thing of the past and our trees and shrubs will be much better off.

Speaking of trees and shrubs, the buds are beginning to swell. For most trees this is not a good time to do any pruning as the sap is rising. However, it is a good time to take a good look at those trees and make notes of any branches that need cut back later in the season.

As for those most famous trees in D.C., the cherry blossom expert Rob DeFeo predicts peak bloom to be March 29-April 3. If you have a chance take a walk around the pool, it is heavenly. In fact, this year might be a good idea since next year marks the 100th year of their arrival from Japan and I am betting it will be swamped.

One more note on shrubs: If you are like me, there are times in the nursery where you see something that just catches your eye and you have to have it, but you don't know much about it. I had Clethra shrubs last year that I swore were dead and about to pull up when lo and behold just a little more warmth and they had leafed out, strong as ever. Our beautiful crape myrtles are a prime example of shrubs that are very late to come out of winter dormancy, so be patient. If you are really curious you can scratch a branch and if there is a green layer beneath , you know the plant is still very alive.

This is also that time of year, when late season freezes can be a concern. As noted in my last post, some plants can take a freeze with minimal damage, like pansies, Lenten roses and early bulbs. However, if you have some early tender plantings that you are worried about on a particularly cold night, a sheet of plastic can be staked over the plants to take advantage of the warmth coming up from the soil. Hardware stores have big sheets of this used to cover floors for paint projects which work well. Just be sure to get it off the next day before the sun shines through or you could end up with plants wilted from the quick heat up. Another trick if you don't have the plastic available is to wet the plants down. The physics of this is that as the water freezes it actually gives off heat and lessens damage. That is why you always see those oranges down in Florida during a cold snap with icicles on them; they have been sprayed to diminish the damage.

I will be back in two weeks to talk more about all the fun and games in the gardens as spring gets into full gear. In the meantime, I welcome all your questions! If I can't answer them, I will get you the answer from some of our local experts.

Capital Weather Gang meteorologist David Streit is also an active gardener. He earned a certificate in landscape design from the USDA Graduate School and volunteered many years at the National Arboretum.

By David Streit  | March 10, 2011; 1:15 PM ET
Categories:  Environment, Latest  
Save & Share:  Send E-mail   Facebook   Twitter   Digg   Yahoo Buzz   StumbleUpon   Technorati   Google Buzz   Previous: Rains so far and coastal & river flooding
Next: Storms wind down, showers continue for now


In the headline, shouldn't there be a comma after "action"?

Posted by: beoods | March 10, 2011 1:49 PM | Report abuse


Good point! Added.

Posted by: Jason-CapitalWeatherGang | March 10, 2011 1:50 PM | Report abuse

I'm confused about my USDA hardiness zone; I always thought we were in zone 7, but I went to the USDA site and entered my 20910 zip code and apparently that is in zone 6. Have I always had it wrong, or have things changed?

Posted by: silverspring9 | March 10, 2011 2:03 PM | Report abuse

I am enjoying your gardening articles. Having just gotten home from my Master Gardening Training class and having spent this past weekend at a M.G. Symposium in Leesburg I find your articles timely. One thing though, we have been told here in Loudoun that it is still ok to prune (late winter early spring) even if buds are starting to emerge as more energy will go down to root production. You want to prune before the leaves come out. You can see what needs to be pruned easier and get rid of crowding and crossing branches which can cause damage. Pruning after leaves are out runs the risk of getting rid of much needed photosynthesis for food for the tree. Now is the time to thin out overcrowding allowing air and sun to get into the trees and shrubs. Have I misunderstood this?

Posted by: worldtraveler83 | March 10, 2011 2:04 PM | Report abuse

Don't prune the azaleas.
So many people do that, they prune the flower buds right off in the spring, then wonder why the shrubs didn't bloom.

Posted by: FIREDRAGON47 | March 10, 2011 2:19 PM | Report abuse

You are right Firedragon47. Spring blooming plants and shrubs are not to be pruned now (M.G. believe never..."right plant right place") but after they bloom if at all. I also learned never to just shear off the tops of shrubs but to go in and thin. Shearing just makes for leggy shrubs and bushy tops. I was referring to pruning trees. I was told that while sap is running, pruning now won't hurt them. People get upset when they see the sap running (i.e. weeping) but it will not hurt the tree. I'm still learning though.

Posted by: worldtraveler83 | March 10, 2011 2:38 PM | Report abuse

Wonderful article! -Katie

Posted by: ThinkGreen | March 10, 2011 2:51 PM | Report abuse

Okay so what about hydrangeas like "Endless Summer"? Should the old branches be pruned back now or will the blooms come from these? I noticed last year I had a couple that grew branches back from the base, which some bloomed from the old branches. Then they died back in the frost. Also, would the spinach and lettuce survive a late freeze if planted outside now?

Posted by: manassasmissy | March 10, 2011 2:53 PM | Report abuse


Check this out:

Posted by: worldtraveler83 | March 10, 2011 3:04 PM | Report abuse


If you live in Fauquier County. I would suggest you call your local VA Cooperative Extension office at (540) 341-7950 (That's yours in Manassas)
They will be able to give you planting times for your area. Vegetables are my next chapter and it looks like your last freeze date may be May 10-15. They can tell you when it's safe to plant seeds and/or transplants.

Posted by: worldtraveler83 | March 10, 2011 3:37 PM | Report abuse

If you need to prune an azalea or other springblooming shrub for space reasons, or when it has gotten leggy, prune right after bloom. At that point, you can prune as hard as you need to (not to a meatball, please!) and you'll get good bloom the following year.

Posted by: fsd50 | March 10, 2011 4:25 PM | Report abuse

I am totally new to the area (from South Florida) Is it too early to plant flowers in hanging baskets, pots, etc? I have a great balcony and I can't wait to have plants and flowers in it.

Posted by: Manny9 | March 10, 2011 4:56 PM | Report abuse

Just went and found several articles that suggest cutting your butterfly bushes way back (to about 1 foot now). And the advice on roses was "you can't kill a rose bush by pruning it", so I think it's time to cut my tea rose way back.

@Manny9--it is too early for any frost sensitive flowers unless you are going to bring them in at night. Things like impatiens, marigolds, petunias, etc will croak otherwise. But you can get pansies and other cold hardy flowers at garden centers right now.

General frost date here is late April. But it varies wildly. My community garden and home are less than a mile apart, but each is its own microclimate--the community garden isn't sheltered and plantings by my house are.

Posted by: concepcion611 | March 10, 2011 5:27 PM | Report abuse

Thanks David! This is great.

@silverspring9 -- we're right on the edge of USDA Zones 6/7. DC is Zone 7, Silver Spring is 6. If your garden is in a sheltered area, you might be more like a Zone 7.

I still can't get over how early things are here, having learned to garden in Zone 5 (Iowa). This year my daffodils were sprouting on New Years Day and are now ~8" high. The hydrangeas are getting green leaves and the heucharas are beginning to wake up.

Posted by: kperl | March 10, 2011 6:01 PM | Report abuse

Two weeks? We have to wait two weeks for another gardening column?


Posted by: waterfrontproperty | March 10, 2011 11:23 PM | Report abuse

@Manny9 - Generally most garden centers keep up with the season so if you go into any local center they should have things you could put out now like pansies.

I think even the Home Depot & Lowes only have cold hardy things like lettuce & pansies out now.

Local garden centers also a great source of info when it comes to things like this, there's usually someone there that will gladly answer any & all questions.

Posted by: wadejg | March 11, 2011 9:16 AM | Report abuse

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