Friday, May 25, 2007

A Paean to Gold and Chartreuse

Mid-spring is here, and we can now take for granted the ubiquity of green leaves. But it wasn’t that long ago that brown twigs dominated the landscape, and even the scraggliest of spruces was a welcome sight in the garden. Most evergreens are needle-leaved, which limits the textures available to us in the winter, but of course there are some tough broad-leaved evergreens.

In colder climates such as my own zone 5, the role of the broad-leaved evergreen is most commonly filled by members of the Ericaceae, the heather family. These include the Rhododendron/azalea, Pieris/andromeda, Kalmia/mountain laurel, and Erica & Calluna/heath & heather. All can be quite beautiful, in or out of flower. But almost all of them must have acid soil, while a few tagged as “lime-tolerant” can really just handle neutral (pH 7) soil, lest they suffer from mineral deficiency, discoloration, slow growth, sickness and even death.

Most of the northeast has acid soil, but as I noted in an earlier post (“Should You Buy Shrubs At The Supermarket?”), the particular mountain ridge I live on (in Adams, MA) is made primarily of limestone, such as is most visible at the Specialty Minerals site on route 8, where the base of Mount Greylock is ground into products such as Tums.

If your soil is really mixed up with limestone particles, you can’t as a practical matter acidify it except by putting in a lot of new soil in a raised bed. But if you already have a Rhododendron, it couldn’t hurt to add an acidifying fertilizer such as Holly-Tone, and perhaps some peat moss, to the surface, then cover with mulch. (Rhododendrons have very shallow roots, so you should not try to dig things in.)

With the Ericaceae impractical for many of us, the preeminent broad-leaved evergreen in this area is Euonymus fortunei, the wintercreeper, especially in a few variegated cultivars such as ‘Silver Queen’ and the similar ‘Emerald Gaiety’ – which have white leaf-edges; and also ‘Emerald ‘n Gold’ – which has golden leaf edges. Many people around here seem to have one of these variegated evergreens, especially the former white/silver types.

I am not generally a fan of variegated cultivars of garden plants, because most of them have reduced vigor, look sickly in the summer, and are very picky about getting enough sun (since they have reduced chlorophyll) but not too much sun (lest their pale portions burn). But these Euonymus fortunei cultivars usually look very healthy, and being evergreen bushes they don’t have to start from nothing each year, but can defend their territory quite well once they are established. The white/silver ones especially can look magnificent at all seasons, provided they are given room to spread naturally.

The variegation of ‘Emerald ‘n Gold’ is claimed to turn an attractive pinkish in the winter, but most I have been watching actually spent much of the late winter and early spring with a lot of their leaves looking like sickly pink-brown winter-kill. Right now, however, all signs of winter damage are gone, and the shrubs’ leaf edges are an especially bright chartreuse, as in this picture:

Unfortunately, I think that most of these bushes aren’t used to best effect. First, these rather slow-growing shrubs naturally have a beautiful form, with branches jutting out here and there in an informal, yet clearly noble, display. But most were placed where they cannot spread to their full size (perhaps 7 feet wide, but probably not for more than a decade after planting), and so eventually they are cut back to relatively smooth-surfaced globular shapes, often with hedging shears. Second, these bushes’ unusual color, especially in spring, calls out for some more dramatic contrast than green & gold versus just green or green & silver. How about some red, mauve or blue late tulips, early peonies, roses or Dianthus, as in the picture in this link from "Kachinagirl"? (I’m not allowed to actually show the photo here.)

By the way, I believe that the mystery shrub with no leaves in “What Would You Do With This Shrub” (April 18) is a Spiraea japonica or Spiraea x bumalda hybrid, such as the popular ‘Anthony Waterer’ cultivar, which will have flattened bunches of pink flowers in another month. Here it is in a photo taken a week ago:

It looks remarkably good for having been such a congested bunch of sticks a month earlier. Such a bush would be: if a Forsythia, or most other genuses, bare-legged; and if a Hydrangea, at least 50% dead wood.

Sunday, May 20, 2007

Savoy Mountain State Forest Blues

I did a day-trip to the Savoy Mountain State Forest today with my family. As a family outing it was less than a success, given bugs in our faces, a wet hiking trail, and a grumpy little girl. But they have a nice looking campground (tent sites with picnic tables and grills, some cabins, bath facilities) which was empty, and a couple of ponds (with perhaps 8 men fishing).

Also, I saw some interesting plants I've never really noticed in the wild before. First, a Trillium erectum (aka purple Trillium, or Stinking Benjamin, seen here with aforementioned little girl). It's a full foot and a half tall, hence its specific name. I only saw one cluster of two of these flowers.

Second, an Erythronium americanum (yellow trout lily) which is closely related to the pink-flowered E. dens-canis (dogtooth violet). These plants were all over, but only two or three were in the full flush of bloom, that I could see, with many holding on to maturing seeds, and many as yet unflowered. Like the Trillium, its flowers nod downward and aren't all that showy from above (but not hard to find due to their brighter color). I have a couple of the similar (yellow) Erythronium 'Pagoda' in my garden, but here's the Savoy wilding:

Finally, it's interesting to see how far the garden Viburnum has come from the wild type we see in our local woods, Viburnum dentatum [CORRECTION: I was in a rush to watch the Sopranos, and misidentified this shrub: it is almost certainly Viburnum lantanoides, the Hobble bush]. Part of the difference is genetic, of course, but part comes from the limited sun in the woods, even along a path. Most wild shrubs are understory plants which grow healthily in the shade. But most can also handle at least half sun, and can thereby gain a lot of extra energy for fuller growth and flowering.

Thursday, May 10, 2007

Wake Up! There’s Been A Slaughter Here.

While gardening, I tend to listen to my iPod. As in my car, most of the time I’m listening to the Grateful Dead. But when I’m slaughtering weeds, especially if with my weedwacker, I listen to The Doors. Today I wacked the Aegopodium, as seen in this photo. Of course, that and the earlier Roundup treatment won’t be sufficient to kill it. But it’s been weakened a bit until I cover it with newspapers and mulch, or a hideous blue tarp.

In other news of plant slaughter, last year I cut down two medium-sized trees in this garden. But I had a third tree, a fairly large Norway maple with about a 20” trunk diameter, which was crowding two other trees, and was awkwardly positioned on a steep slope looming over the street and some lilacs.

So yesterday I had some local arborists over. People I play cards with were agreed that I’d get the best price, at least among businesses with insurance and proper safety equipment, from these guys:

It was pretty impressive how quickly they could climb up, cut down and clean up a hardwood tree.

Of course, there are divots in the lawn where pieces of trunk were dropped from high above – that’s inevitable.

In a fairly normal snafu, the bulk of the tree got a bit out of control on the slope. It was stopped by a heavy rope (and 5 guys), but not until damaging a lilac by bending it to the ground. I lopped off the larger, split trunks of the lilac today, leaving several younger canes; this pruning might have been a good idea anyway.

Here you see the difference between one of their saws and my little (16”) McCulloch, which has almost exactly half the engine displacement.

I can’t imagine using such a large saw while up in a tree. Size apparently isn’t the only difference. As the climbing guy explained to me, professional and home-use saws differ subtly in the construction of their chains, such that an amateur who buys a professional saw is apt to have it bite and kick into them, sometimes with catastrophic injury. I could not fathom exactly what advantage this saw blade of death had for him.

Tuesday, May 08, 2007

Fritillaria Look Upon Menacing Neighbors

My Fritillaria meleagris (snake's head fritillaries) are blooming. Here we see them facing the menace of aggressive neighbors -- not in the 100-year-old house at top, but rather the Lonicera stump behind them, sprouting freely now in its attempt to recreate itself as a 10' x 10' bush, and the Aegopodium podagraria groundcover which has spread around and well beyond them. Both invasives are covered in the previous post.

Monday, May 07, 2007

A Tale Of Two Invasives

The Japanese, or so I have read, believe that you can make a fine garden out of a wild piece of land with nothing but a cutting tool, such as a pair of pruning shears. Naturally, you can use them to kill or control the existing plants, but cannot add any new plants.

By this method it takes a couple decades to achieve anything of true merit. At that point, you are going to have one of those minimalist gardens with a handful of species, including a lot of moss, some rock, and if you’re lucky perhaps one flowering plant providing a week or two of non-green color. These are serene places for tea ceremonies and meditation. But I don’t have that level of maturity or patience, nor do I expect it from my pre-school children. So I am not trying to emulate a “knife-only” garden.

But I am trying to discover what has been growing in my new (to me) garden, and what is coming back from root or seed now that I have removed two fairly large forest trees. And I do aim to give existing plants every chance to prove their merits, to use the knife judiciously.

As the Japanese well know, one of the best plants to keep in place as a groundcover in a shady setting is moss. I “mow” the weeds, or unwanted plants, off of it with a pair of scissors, to give the moss the upper hand. Pulling out the weeds would not work here, as the delicate moss would be ripped up with root-held chunks of soil. Of course, as with grass mowing, I will have to do this more than once, but unlike grass, moss mowing will be needed less frequently as competing plants are killed off with repeated cutting down to the dirt – if I do it frequently enough.

Here you can see the results of an almost-finished first-time cutting, with bare patches evident and some loose detritus remaining. While sitting on my butt doing this I get to pick and choose which of the other plants get to survive unscathed; I have left an unknown succulent (probably a Sedum) at the top of the photo, as well as the Eranthis (blogged on earlier when it was in flower) at right.

Naturally, in a wild place you’re going to see more brambles than Trilliums, and more wildings than choice cultivated plants. In this next photo, you can see two of the “worst” invasives.

The stump is the remains of a large bush I cut down last fall. It is probably a bush honeysuckle, one of several Lonicera species which is taking over our woods. It took a long time for me to tentatively identify these (I have several) because they are “old-fashioned” plants which were sold 100 years ago when my house was built, but are not widely available now. Indeed, it is not PC to plant such a bush, and environmentalists sometimes hold invasives cleanups, where they cut them down in the woods and paint their stumps with Roundup (imagine, environmentalists with Roundup!)

Like most bushes with red berries (e.g. Euonymus alatus, Berberis), Lonicera attracts birds, which eat the berries and then poop out fertile seeds all over the place. These shrubs have taken over many lightly wooded areas, shading out and outcompeting native flora.

Personally, I think a vigorous bush with nice-smelling (albeit not very showy) flowers, nectar for pollinators and berries for birds, has pulled its weight in the grand scheme of things. And so I am going to let some of my Lonicera live, at least for a while. Some I have pruned modestly. Some I have killed. Others, like this one which was pushing up against a handsome native dogwood (Cornus alternifolia), I cut to the ground last fall, expecting it to come back. Here we see that it is already re-sprouting strongly. I will probably use selective pruning each year to keep it within bounds.

Around the bush is a groundcover of the same color. This is the infamous Aegopodium podagraria. A lot of people have planted this in its variegated form, and lived to regret it. It spreads by rhizomes and seeds. This nonvariegated form is even more invasive. It will either be stopped forcibly, or it will take over every inch of garden earth.

It is a lot more work to clear out a small, herbaceous plant like this than a woody plant like a shrub, which grows relatively slowly and can’t propagate until it is of quite a noticeable size. I have been pulling up the Aegopodium, but it breaks off at the surface, leaving a thick nodule right below the soil surface. So the scissors are just as effective. I have also been painting its leaves with Roundup, to modest effect after a week, and may use a tarp or newspapers and mulch on larger areas (it fills a circle about 20 feet across, not counting a vanguard which has crossed a path to infest a patch of daylily).

Getting it all will likely take two growing seasons, even if I remain super-diligent.

But for this year at least, I have made my peace with the Lonicera. I am open to the suggestion that it is wrong for me to allow a red-berried foreign invasive such as bush honeysuckle to remain in my garden. But if we are obligated to remove plants for this reason, I don’t see how I can destroy the Lonicera without also taking action against the giant Norway Maple which shades almost my entire house, but which has left perhaps 10,000 seedlings in my yard this year.

Friday, May 04, 2007

Should You Buy Shrubs At The Supermarket?

The local supermarket in Adams (Big Y) has put out a display of shrubs for sale. The specimens look healthy, and prices are right, at $13 for a 2-gallon pot. However, I expect that most of these plants will not meet their buyers’ expectations. Why is that?

First, most of the plants are in the Ericaceae, the heather family, and will only be healthy in acid soil. These include several Rhododendrons and azaleas, and a couple cultivars of Pieris (as seen in this picture), also known as Andromeda. However, most everyone’s soil around here rests on limestone bedrock, and is mixed with limestone pebbles. As such, it is almost certain to be alkaline, not acid, except in raised beds built up with peat moss, in places with deep humus-rich forest soil, or where people have used acidifying chemicals, such as sulfur or Holly-tone fertilizer.

This is not a mere hypothetical problem. Compared to those in the suburbs of Boston, Rhododendrons and their acid-loving cousins almost always look sickly in this region, and even some that are apparently healthy often have the subtle distress signs of chlorosis, such as leaves yellowing, with green veins (second picture, taken in North Adams).

Another plant with a large display at the Big Y (Hydrangea ‘Endless Summer’) is shown on its label with bright blue flowers, but it will probably be pink (and perhaps chlorotic) in most people’s gardens, again because the soil is not acid. The fine print on the Hydrangea label does state this color effect, but for the rest of the acid-loving plants, only some of the labels inform us that the plant needs acid soil, and some don’t.

Besides, the Big Y is not a specialty plant nursery. It is an impulse purchase point for people who are generally not very garden-knowledgeable. It is not reasonable to expect this broader public to know whether their soil has a high (alkaline) pH. Even if everyone did know this, it still makes no sense to offer a limited display of plants, the majority of which are unsuitable for the local conditions.

The other big problem is some of the plants are of questionable hardiness for our Zone 5 climate. To go back to ‘Endless Summer’ – this is a Hydrangea macrophylla cultivar. Most H. macrophyllas are rated hardy only to Zone 6. While there is some controversy on the matter, this cultivar is probably bud hardy in protected (nonwindy) areas in warmer parts of zone 5. But there aren’t a lot of places around here which don’t get much wind. (The cold wind is the other reason Rhododendron and Pieris often suffer hereabouts.)

The plant will survive our winters, but it will likely have significant die-back – including most of its overwintering flower buds – in many if not most winters. Yet this shrub’s label simply says that it’s hardy in Zone 4. It also claims that the plant will bloom throughout the summer, first on its old wood (i.e., on overwintered flower buds), and then on new wood. This reblooming feature means it should in fact bloom here in late summer on its new wood, but again, the earlier blooming on old wood is highly questionable in a zone 5 garden. (Because of dieback, it also probably won’t attain its expected size of 4 to 6 feet.)

Finally, one of the plants was a cute “Alberta Spruce.” Generally this variety of the white spruce species (Picea glauca var. albertiana) is sold in its ‘dwarf’ form. People are often surprised that these dwarves eventually grow to 15 feet tall. But in this case, the plant isn’t a dwarf at all. It is expected to grow up to 60 feet tall and 20 feet wide. Fortunately, this fact is on the plant’s label, but I question whether it makes sense to include such a tree, because most people are not out making impulse purchases of 60-foot forest trees, and at least some people who buy this plant probably aren’t going to notice that that’s what they’ve got, especially given its name and similar appearance to the popular dwarf spruces. Of course, it is a lot quicker and cheaper to grow a non-dwarf spruce to the 2-gallon size than it would be to use a real dwarf cultivar.

I don’t expect the Big Y to have dedicated shrub buyers, but you’d think they could find somebody in the headquarters who has done some gardening and has given some thought to what grows in the area. It’s not like they’re down in Bentonville, Arkansas or something.