Tuesday, April 1, 2008

National Arboretum Magnolia Collection

There is an engaging lack of subtlety to the Magnolia Collection when the flowers open. Line, form and structure become subjugated to a sensory overload of perfume and color. Passing between trees laden with thousands and thousands of lush flowers, one heady perfume gives way to another, you cover ground strewn with pink, white, yellow petals. Actually what seem to be petals are "tepals", a fusion of petals and sepals. They clearly have substance; thick, rich and textural, the fragrance seems only a natural complement. All this opulence sits at clear counterpoint to the evanescent delicacy of the Flowering cherries, definitely more New Orleans than Japan.

I wouln't want to have to choose, although I suspect that at base I am a magnolia man. I have never been accused of subtle delicacy. The magnolias always begin flowering before the cherries, but there is overlap; this year they are approaching simultaneity. The coming weekend (April 5-6) will be great. If you can possibly visit the Arboretum for even an hour or two, you owe it to yourself to do it.

Magnolias are good garden plants for this area. They don't mind our summers, they are okay with clay soils, they grow as quickly as any other group of woody plants, they have great looking large, furry winter buds, and they look good with their leaves off. Their one drawback as landscape plants is rapidly disappearing as global warming keeps spring temperatures high. It used to be that the early flowering cultivars, if hit by a late frost, would blacken and rot. This doesn't happen so much anymore. Cultivars, eg. 'Galaxy' (a USNA release) have been introduced that start flowering later and late severe late frosts are becoming less and less common occurrences.

Monday, March 31, 2008

I have a confession to make...

Okay, I grow this plant, Polygonum cuspidatum variegatum;I'm not proud of myself but I love the orange colored shoots that force their way out of the ground...well, now. If you know a bit about invasive plants, you may know that the parent species of this plant is a dangerous invasive colonizer native to Japan that has been introduced throughout the world. Officially designated a noxious weed in the State of Washington, it is a much more serious problem in Great Britain.

There are a number of variegated forms and the unaggressive nature of this clone is generally acknowledged but never explained. The species is dioecious, meaning that the flowers are either male or female and the individual plants are either male or female. Apparently all the Japanese knotweed in Great Britain is a single female clone!

I grew this one for 10 years in a barrel and it never moved beyond a tight clump in the middle of the barrel. I always watched it suspiciously worrying that the vigorous rhizomes would force their way out of the container and into the soil. I was prepared to kill it at any time. Well it never escaped and I never felt compelled to kill it. At some point, the barrel rotted and I planted the Knotweed in the ground. I watched it even more carefully. Five years and no problem but I know that doesn't mean I can relax and frankly after making this public confession I am going to enjoy the shoots one more spring and next month it will die.

Sometimes we grow plants for funny reasons; like the shoot color of new growth. I guess sometimes we have to kill them for other reasons. Removing a plant from the garden always comes with an upside. Room for new plants!

Sunday, March 30, 2008

Post Planting...Pre Growth

What a difference a week can make! (see post of March 28) I offer this picture with some trepidation, being very suspicions of gardens that look good as soon as they are planted. The word "over-planted" inevitably leaps to my mind. I guess the good news is that while it does look better than it did last week there is certainly room for improvement; more good news is that the vast majority of the plants here are herbaceous perennials so they will grow significantly this year.

The owners wanted flowers, a pool, year-round interest, a small raised bed for vegetables, and some turf for their dog! Its a good thing that they have a relatively large lot! In a situation like this evergreen perennials can serve double-duty, providing both permanent structure and flowers. We used a number of these "sub-shrubs": Delosperma, Dianthus, Erica, Sedum spp., Iberis, Thymus, Lavendula, et alia. Most of these plants are happiest in hot, sunny, dry areas; since this garden faces SE, they will be very happy. Grasses with their architectural forms will provide additional structure. Most of the non-evergreen perennials are either native species or cultivars of natives, which will attract butterflies, hummingbirds, and other interesting fauna. Many sun-loving perennials are meadow plants which tend to flower mid-summer or even later. We can take another look at this garden in late-July or August.