Saturday, July 5, 2008

Summer Color at Behnke's

Early summer, now that is, is one of the most colorful times at a Nursery (or Garden Center). The annuals have all been potted up from Market Packs or 4" pots to 5" pots or larger. Plants that had been struggling in a few cubic inches of soil are now happily growing roots into a quart or more of soil; the happy roots are reflected in happy tops with an abundance of blooms. Cannas are blooming, and Lotus and flowering tropical patio plants. This picture is part of the Annual Area at Behnke's Nurseries in Beltsville. I worked at this Nursery (they do grow many of their own plants son its more than a Garden Center) for a long time and my wife worked there longer.

It isn't just the annuals and tropicals that look good now. Hundreds of flowering hydrangeas under a lath roof are pretty impressive. Crape Myrtles have begun to flower and there are blocks of hundreds of large flowering shrubs and smallish trees in colors from white through pinks, reds, and purples with a few corals thrown in for good measure. Crape Myrtles have been extensively selected and hybridized and there are varieties that vary from low groundcovers to 40' multi-stemmed small trees. And of course the Buddleias that we ought not grow are all flowering, luring butterflies in for the praying mantids to harvest.

Most Garden Centers carry plants in much greater quantities as they come into their peak season and most grasses are at their best from summer to fall. Daylilies are peaking now so there are many cultivars flowering and available this month. I bought a nice Hydrangea yesterday and a variegated Salvia greggii. There are plants out there for the obsessed. I mean the interested.

Thursday, July 3, 2008

The Symposium: A Group of Students and Teachers Eager to Learn about Watering From Eachother

If you are either old??? or wise you can skip this post. I am 56 myself which I am certain is above the median age of the world and am fairly certain, the US. That means a few things, two of which are: one, since I spend an inordinate amount of time thinking, I have developed many theories regarding the functioning of the world, and two, since reticence, restraint, and common sense seem to leach away with the passing of time, I am happy to share these ideas with everyone. Here's the thing: I'm right about this one!

've pretty much narrowed it down to Feedback. Feedback can make you better at anything from sex to watering plants (which is the ostensible subject of this post!). Here's how it works: when you approach a situation where you will be making choices and taking action you have to start by accumulating as much theoretical insight as you can; I will suggest some pointers regarding watering, you're on your own as to sex.

We know plants need water, we know that most plant obtain most of their water through their roots. We know water moves from the roots up through the plant and is ultimately lost to the surrounding air by diffusion through stoma (adjustable openings in leaves, mostly). This entire process is called transpiration. When it's hot more water is lost through this process. Lower humidity means more diffusion and more water loss. Soooo we are all pretty much on the same page in wanting to water more in the summer when it's hot. Things can get complicated though, Some plants respond to extreme heat by slowing down their processes, essentially going dormant. With limited root function, too much water will drown these plants. On an 89 F day with 79% humidity and no wind, most plants will use less water than they would on a 70 F day with 20% humidity and 15MPH winds. This is just one relatively simple example of how complicated things can get. Don't despair; plants are tough and we become more sophisticated waterers as we gain experience.

That is if we accept Feedback, we take an action in a situation, examine the results and if it works we go with it and if it doesn't work we try to figure out why and try another approach, and over and over. This sounds simple, and of course we all do this every day, but to do it most efficiently you have to really look closely, objectively, and honestly at the plants. This sounds easy but it is not. Keep trying though, it gets easier with time. Try not to be ruled by fear also; everyone's first instinct on seeing a wilting plant or one with yellow leaves, is to add water, and while that is often, okay usually, the right thing to do it isn't always and when its not, watering can often do serious harm. Okay I'm done; someone else wants the soapbox.

Wednesday, July 2, 2008

Datura meteloides: the Sacred Datura, A great plant for night gardens

I like them big (this gets ~4' x 4'), I like them fragrant, I like them flashy, so you know I love this plant. 6" intensely fragrant trumpet-shaped flowers open in the evening, stay open all night and close as the sun rises in the morning. I know Georgia O'Keefe would have, actually did love this plant; it was a favorite subject of hers. Native in her adoptive home of Taos, NM, it is a handsome plant. Could be considered coarse? Certainly not by me or any reasonable person. It isn't delicate, though I actually saw someone refer to it as delicate in a chat group.Maybe they meant the fragrance which is delicate compared to, say a Gardenia.

Native to the near-desert areas of the Southwest, it tolerates considerable heat and dryness and doesn't seem to have that aversion to humidity that sometimes comes with those SW plants. The seedpods are interesting and dangerous, the size of small hens eggs and covered with short sharp prickles. If you see a plant in the garden of a friend or acquaintance, or someone who's not looking (Did I say that? Ignore that.) and it has a ripe seed pod you will be doing them a service by removinf it and planting the seeds in a sunny dry part of your own garden. It is pollinated by moths as so many night-blooming flowers are, and it is claimed that the Hawk Moths become intoxicated with the pollen. Could be; Datura is in the Nightshade Family, Solanaceae, which is chock full of potent chemistry. Many are seriously poisonous, like Deadly Nightshade and Jimsonweed; the latter contains among other good chemicals belladonna and scopolamine which were compounds historically utilized by a variety of pagan religious groups.

Like the other moth-pollinated flower we were discussing a few days back, Yucca rostrata, this is a situation that seems slanted in favor of the pollinator. In both cases, the moths feed on the pollen, inadvertently pollinate the flowers, lay their eggs on the plant and their progeny devour great quantities of the host plant. But do not fear, enough seed survives to carry the Datura (actually an herbaceous perennial in warm place) to the next generation and enough of the Yucca seed survives to produce members of a younger, genetically invigorated, generation, Aint love grand!

Tuesday, July 1, 2008

We really needed that rain.....well maybe not desperately

One of the many things that we do at the US National Arboretum is keep Weather Records. We keep daily data. The picture shows the monthly sheet for June 2008. Seems primitive doesn't it. Handwritten and all. We record the high and low temperatures, the precipitation type and amount, and conditions at observation (we do the weather at 8:00 AM 365 or 366 days a year.
We use a recording digital thermometer, but we measure rainfall from a standard rain gauge and we have to look at the sky manually. Joke, sorry. We submit the data to NOAA via the internet daily, but still keep these sheets!

If you click on the page you will be able to see in the farthest column to the right, the cumulative monthly rainfall: 7.72". Thats a lot for June, or for any month for that matter. Normal rainfall for the month at Reagan National Airport is 3.13". Though we have more than doubled that, we are only halfway to the record high which is 14.02" and which was recorded only two years ago. The driest June on record was 1940 where they measured only .86"; we approached that minimum record last year with 1.36".

Anyway its a wet year, our year to date precipitation is over 30" and that's over 2/3 of what we would expect to get in a year. It only took 6 months and we seem to be in a pattern from which we can expect more. In Fern Valley, and I assume throughout the rest of the Arboretum (and in the Adelphi Garden) we have not had to do supplemental watering yet. By this time last year, the hoses and the rainbirds had had a good workout. That's the good news, on the down side is the fact that the numbers of weeds are unprecedentedly high and they are reaching remarkable sizes. Oh well. I would rather weed than water.

Monday, June 30, 2008

Ed and I walked through the daylilies at the end of the day. They are peaking!

Tucked into the Boxwood Collection here at the Arboretum, are a few other interesting smaller assemblages of plants; Tree Peonies, Narcissus, Daylilies, asst perennials. The Daylilies are just reaching their peak. This would be a good weekend to see them. Meadowlark Gardens, in Northern Virgina, also has a good collection of Daylilies, which, like Lynn (the Boxwood/Daylily curator at the USNA), they have chosen to plant on top of their Narcissus collection.

I go back and forth on daylilies; their flowers are undeniably beautiful and they come at a good time, that is when the high season perennials have gone by. But their foliage is so darned messy that I don't know where to put them. I used to insert them as accents, sort of deciduous flowering liriopes, into semi-formal or ever formal areas, but when the leaves go yellow, they do become eyesores. Nowadays I am more apt to treat them as cut flower plants and mass them along the sunniest back side of a house so that they can be appreciated without applying the daily cleaning and grooming that they would require in a formal front garden.

At any rate there are thousands of varieties and some of the flowers, see 'Ruby Spider' are..., well look at those flowers. In fact they are good cut flowers though they last only a day. I once visited a hybridizer when his plants were in full bloom and he had at least 200 individual flowers in "compound vases" in his living room. Cool display. And if the messiness still gets you, I have learned that it does no harm to the plant to cut it back to 6" or so after flowering; the foliage regrows nicely and stays clean for the rest of the season.

Sunday, June 29, 2008

10 Year old planting of Canna 'Bengal Tiger' at our local Safeway. This is a truly hardy canna!

I had a "plant dream" last night; actually it was more a "nursery dream". I was in a small super nursery. Of course the plants were unbelievable. Sculpturally contorted succulents. Alpine buns with flowers all the colors of the rainbow, tropical foliage plants with leaves the size of tabletops, and vines with flowers so sweet smelling that....It was sort of a Venice with plants with canals everywhere. The beds were islands and while there were any number of small rickety bridges, occasionally a canoe or small skiff was necessary to move on.

The proprietress was clearly a gruff composite of women I know who own small Nurseries. She was no nonsense, clearly a person who loved plants and could choose excellent ones, but who still intended to operate a business at a p;rofit. Hello Martha and Darby! Native plants weren't isolated in a group, but they were there and nice ones too.

I think this dream was my unconscious rejecting a post I have been working at for a week or so in which I tried to promote "boring" plants, plants like Wax Begonias and Rose-of-Sharon, and Caladiums (that I actually like a lot). I guess I'll let that one go!