Wednesday, July 1, 2015

Summer Gardening and Flowering Plants

It is July, and though the solstice has passed, true summer is bookended by Independence Day and Labor Day, two months’ reward for seemingly six months of winter. Time is set aside for travel, vacation, summer camp, rest and relaxation. However, it is still a good time to garden, despite the old notion that it is too late in the season to plant. Indeed, this used to be true: when plants used to be field-grown for transplanting into a new garden, digging them up in the summer was risky business. Today’s plants, from trees, shrubs and vines to perennials, are grown in containers to make their transition into the ground practically stress-free. While it is true that summer additions to the garden must be watered, it’s equally true for those plants that were put in this past spring. (Please, don’t rely on lawn irrigation systems to do the job for you, unless you have a dedicated drip zone. Lawn irrigation does not water deeper-rooted plants sufficiently.)

The fireworks that light the skies on the Fourth are echoed in the flowers of summer, as July and August are the months of Coneflower (Echinacea) whose large bright daisies burst into dazzling and clean displays of traditional dusky pink (such as the standby cultivar ‘Ruby Star’,) but newer hybrids now offer shaggy mop-headed types such as the orange ‘Marmalade’ and ‘Hot Papaya’. ‘Evan Saul’ (Sundown™) evokes a desert sunset, with bright orange “petals” highlighted with rosy-purple. ‘Green Jewel’ offers cool light green “petals” – a unique color – surrounding a central green cone. Coneflowers are butterfly magnets, and their brown seed heads are prized by finches in late summer and beyond. They all do well in sun to part shade, and are drought-tolerant once established.

We are well-stocked with interesting and well-grown trees and shrubs. Our specimen Stewartia tree planted beside the barn has been flowering since June 20, and is just halfway done blooming, an inspiration for the smaller ones we have ready for planting. Summer-blooming azaleas are hardy, colorful and fragrant, and are superb for planting near a deck, patio or pool, where their sweet scent may be enjoyed in the day or evening. Several varieties are offered, and are in flower now. Buddleias (Butterfly Bushes) are budded and will be opening soon, as will the many types of Clethra (Summersweet) that we carry.

Ornamental grasses are now coming into their own, and will only continue to get bigger and better through the season. Plant them now to enjoy through the fall, as most types need the warm soils of summer to become established before winter.

Astilbe at The Mixed Border
And for the shadier gardens, our Hostas are spectacular, as always. We have on hand over a hundred varieties, from tiny-leaved miniatures such as ‘Baby Booties’ to ‘Empress Wu’, the largest Hosta to date, and with a wide choice in leaf colors and patterns of variegation. Astilbes are coming into flower, and we have a good selection of perennials, wildflowers and ferns for shade.

We welcome your visit.

Nursery Hours, July to September:

Monday: 9:00 am to 5:00 pm
 Thursday through Saturday: 9:00 am to 5:00 pm
Sunday: 10:00 am to 3:00 pm
We are closed on Tuesdays and Wednesdays, except by prior arrangement.

Please note that in the event of dangerous weather (such as thunderstorms or extreme heat) we may close earlier than scheduled, for everyone’s sake. Please call ahead (603-882-5538) if bad weather is forecast on the day of your visit.


Thursday, May 30, 2013

Selecting, Planting and Caring for Peonies

We offer both herbaceous and woody (or tree) forms of peonies. The most familiar garden peonies are the herbaceous types, with showy and colorful flowers in May to June, depending upon the variety. Each blooms for a week or more. They are cut down to the ground each fall and rise again in the spring.

Tree peonies maintain woody stems which bear large leaves that drop in the fall, and their flowers are enormous: often up to ten inches across! These blossoms open and fade all too quickly, especially when grown in afternoon sun (although they need at least ½ day of sun to bloom well.) Thanks to the late breeder Mr. Itoh, there are also many “Itoh” or “intersectional” hybrids now available, which have both an herbaceous and a woody parent. These are some of the finest peonies available, with herbaceous foliage resembling that of their woody parent. Enhanced vigor and a longer bloom period, including varieties with yellow flowers, distinguish them from other peonies.

Peonies in The Mixed Border's garden

Flowers are typically classified as Single, which have showy petals surrounding functional carpels and golden-yellow stamens (reproductive parts); Japanese, with large outer petals and clusters of enlarged anthers sometimes edged in yellow; Semi-double, in which inner petals have formed within the ring of outer petals, and still contain functional reproductive parts; and Doubles, whose stamens and carpels have been transformed into a dense display of petaloids surrounded by the outer petals. With the large number of varieties in cultivation, there is often some overlap of these various forms, but I have tried to keep it simple. The Singles and the Japanese forms will tend to remain upright in flower, while the heavier Doubles may flop under their own weight. Support of these types may be recommended to keep the flowers off the ground; a subtle corset of bamboo canes and garden twine is usually enough. Peonies usually require a couple years to get established after planting to display their full floral qualities. Flower color can be affected by strong sun (fading of deeper colors) or cool weather (white varieties can develop pink tones.)

Most (but not all) peonies are fragrant, with the pink or white doubles usually your best bet for a scent that is typically rose-like. Red peonies, though pretty in the garden, don’t always make the best cut flowers, as their aroma isn’t always desirable. Some tree peonies are mildly lemon-scented.

Peony 'Krinkled White'

How to plant peonies:
As long as the planting site is well-chosen and well-prepared, Peonies will live for many decades with little care. Hybrid peonies perform best with at least a half day of full sun, and excepting tree peonies, more is better. If given the choice, some afternoon shade can help to reduce blooms fading in color or “going by” too quickly.

Well-drained soil is important, as areas which remain wet for periods of time may cause their thick and fleshy roots to rot. Because they are so long-lived, they deserve and need a planting hole that is deep and wide, and contains a good amount of organic matter such as compost. Dig a hole at least the size of a 5-gallon bucket and remove the soil, discarding any sand or gravel and reserving the topsoil or loam. To that, add an equal amount of compost (avoid all but extremely well-aged manure) and a handful of lime and organic fertilizer. Fill the hole with this mixture, such that the plant’s soil surface will be at (or slightly above) the soil level outside the hole. Take care not to place soil on top of the roots, either now or at some future time, as their flower buds will not form if planted too deeply. Mulch very lightly with good compost or a thin layer of shredded bark, and water well.

Do not allow the plant to dry out until well-established (usually within one year.) Peonies are drought-tolerant, but may go dormant early and flower poorly (if at all) the next year if not kept reasonably moist throughout the growing season. Fertilize each spring or fall with organic fertilizer.

Peony 'Sorbet'

Peony problems:
My peony doesn’t flower. Why? Peonies planted too deeply may not flower, nor will those grown in poor soil or shade. Keep the foliage vigorous and healthy.

Some of the leaves and flower stems have wilted and turned brown. Botrytis is a blight disease of peonies that happens most often when the foliage remains moist, sometimes due to rainy weather, or because of overhead irrigation (typically from lawn sprinklers.) Clip off the diseased parts, cleaning your clippers with rubbing alcohol between cuts. Throw the diseased stems in the trash. If needed, an appropriate fungicide may be applied as a preventative (but they rarely are curative.)

Friday, April 26, 2013

Selecting and Caring for Clematis

Clematis are lovely and useful plants for the garden. We offer 3 different types: the familiar twining vines, and the lesser-known shrubby and trailing forms.
  • The vines are available as the popular large-flowered hybrids as well as small-flowered hybrids and species. They are typically planted to grow up a lamppost or trellis, but are also attractive when allowed to clamber up a tree or shrub.

  • Shrubby clematis are commonly used in the perennial garden, where they offer late-season color. Most have a rather lazy habit, and can be supported using neighboring plants or stakes and twine.

  • Trailing clematis are the least known, and are typically either tied to a support such as a mailbox or a lamppost, or given the chance to trail freely through a garden.

Clematis are generally easy to grow, providing that certain conditions are met. First, they usually require at least 1/2 day of sun. Afternoon shade will benefit the blossoms of many clematis, especially those with prominent contrasting “bars” in the flowers. A deep, fertile soil is also needed, which can be prepared by digging a hole at least the size of a 5-gallon bucket, and discarding any poor soil. To the better soil, add an equal quantity of organic matter, such as Coast of Maine™ compost. One-half cup or so each of ground limestone and an organic fertilizer such as Pro-Gro™ is also beneficial. Blend all the ingredients, dump the amended soil back into the hole, and plant the clematis carefully, taking care not to damage brittle stems when securing to a trellis or other support. Good mulch helps to keep the soil cool and moist. Water well, and maintain it as you would any new planting.

Large-flowered clematis are susceptible to a disease known as Clematis Wilt. This disease remains a mystery to gardeners and scientists alike, for it is unknown if it is caused by a fungus, wounding of the stems caused by windy conditions or mishandling, or a phenomenon of the plant being unable to provide enough water to the stems during stressful weather. In any event, it is characterized by a sudden wilting of the leaves starting at the tips of the stems, and progressing downward. Benomyl™, a commercial fungicide, is commonly used to counteract it. Pruning the stems down to healthy growth will often stop the disease, and new stems will usually arise from buds hidden below ground. Clematis Wilt rarely, if ever, will kill clematis; at most flowering may be disappointingly delayed. Please note that The Mixed Border Nursery will not replace any clematis that has been affected by Clematis Wilt.

Pruning clematis is often confusing to the uninitiated. However, once you understand that you will not kill clematis either by pruning it according to the wrong method, or by not pruning it at all, it becomes much easier. Clematis are grouped according to the way they flower, and this governs how they ought to be pruned. If you are unsure what type you have in your garden, observe its flowering habits for a season, and follow the recommendations that most closely match what you have. Except for Group 1 types, all may be cut back severely in spring with at worst a temporary effect on flowering.


Group 1:
These plants flower early on old stems and generally do not need to be pruned, except to remove dead or damaged stems. If pruning is necessary to control growth, cut stems back after flowering.

Examples:
Clematis alpina and varieties
Clematis macrophylla and varieties

Group 2:
These also flower on old wood, but a later flush of flowers happens in late summer on new growth. In early spring before buds have opened, prune out any dead or weak stems, and cut back remaining stems to a pair of buds. The lower down the stems you cut, the more flowering will be delayed. Cutting the stems by half is a good rule of thumb.

Examples:
Clematis ‘Amethyst Beauty’ C. ‘Arctic Queen’ C. ‘Asao’
C. ‘Bee’s Jubilee’ C. ‘Belle of Woking’ C. ‘Blue Ravine’
C. ‘Carnaby’ C. ‘Crystal Fountain’ C. ‘Diana’s Delight’
C. ‘Duchess of Edinburgh’ C. ‘Elsa Spath’ C. ‘Empress’
C. ‘Franziska Maria’ C. ‘Guernsey Cream’ C. ‘Henryi’
C. ‘Isago’ C. ‘Josephine’ C. lanuginosa ‘Candida’
C. ‘Nelly Moser’ C. ‘Niobe’*** C. ‘Perrin’s Pride’
C. ‘Piliu’ C. ‘Proteus’ C. ‘Rebecca’
C. Rhapsody’*** C. ‘Rosemoor’ C. ‘Silver Moon’
C. ‘Sunset’*** C. ‘Sugar Candy’ C. ‘Veronica’s Choice’
C. ‘Vino’ C. ‘Vyvyan Parnell’ C. ‘Warsaw Nike’

Group 3:
Flowers are produced on new stems each year, so vines can be cut down to a pair of buds near the ground in late winter or early spring.
Examples:
Clematis ‘Alionushka’ C. ‘Arabella’ C. ‘Barbara Harrington’
C. ‘Comtesse de Bouchard’ C. ‘Hagley Hybrid’ C. heracleifolia and hybrids: ‘Mrs. Robert Brydon’
C. integrifolia and hybrids C. ‘Jackmannii Superba’ C. ‘Niobe’***
C. ‘Perle D’Azur’ C. ‘Petite Faucon’ C. recta and varieties
C. ‘Rhapsody’*** C. ‘Roguchi’ C. ‘Rouge Cardinal’
C. tangutica and varieties C. ternifolia (aka C. paniculata) C. texensis ‘Duchess of Albany’, ‘Odoriba’, ‘Pagoda’
C. ‘Ville de Lyon’
C. viticella and hybrids:
C. v. ‘Mrs. Betty Corning’ C. v. ‘Etoile Violette’ C. v. ‘Kermesina’
C. v. ‘Polish Spirit’ C. v. ‘Purpurea Plena Elegans’

***Note: these varieties may be pruned according to either Group 2 or Group 3.
Photos courtesy of Donahues Clematis

Thursday, March 7, 2013

The Best Hardy Plants for New England

Despite the recent snowstorm, our thoughts have been turning to spring which, according to the calendar, arrives on March 20. True spring weather usually takes a while to catch up to the Equinox, so it will be April at least before the ground is soft and dry enough to plant. Still, just before the snow fell, our Snowdrops were in full flower under the beech tree, and the fat budded blooms of Hellebores had already popped through the unfrozen soil. Once the snow melts, they will resume their awakening to flower in early spring, as they always do. Exotic witch hazels (not the late fall-blooming natives) have been in flower since early February, uncoiling their gold, yellow or orange ribbons on warm days, and retracting them at night. Bringing their cut branches into the house persuades them to release their pleasing perfume.

While we can only enjoy (or imagine) these garden delights (Winter flowers? In New Hampshire? Yes, they are possible, and easy) -- it’s not too soon to start planning.

Let’s face it, choosing ornamental plants can be a daunting task for new homeowners and otherwise inexperienced gardeners looking to landscape their yards. For some, a trip to a well-stocked nursery displaying a wide selection of plants can be as confusing as traveling to another country where people speak a different language and whose culture is unfamiliar. Questions of “Is it hardy?” “Will it do well in my yard?” “How much care do I have to give it?” immediately come to mind. It’s no wonder that one often sees the same plants repeated from one house to another, as though each garden was painted from a common palette. Yews and rhododendrons, arborvitae and azaleas, burning bushes and junipers dominate the planted landscapes of New England, because it’s easiest to repeat what is known.

But repetition isn’t always the best way, especially when repeating mistakes. Most of the more familiar plant choices mentioned above grow too large for the average “foundation” planting, and without regular pruning (which is typically more akin to hacking,) will soon cover up first-floor windows and grow over the walkways. And relying on a limited plant palette leads to boringly similar yards.

Better nurseries will have well-trained staff to assist in the process of selecting the right plant for the location, as well as helpful signage and tags. Experienced garden designers are familiar with a much broader range of plants, and know which will not only do best, but also perform and look well with little maintenance, and will arrange them in a distinctive fashion.

Another resource for New England gardeners is to seek out the list of Cary Award-winning plants. The Cary Award program (www.CaryAward.org, a non-profit entity established and administered by the Worcester County Horticultural Society) is bestowed upon hardy woody plants that meet certain criteria: they must be hardy to at least 2 of New England’s Hardiness Zones (but are generally hardy to at least Zone 5 if not colder;) they must offer more than a single season of beauty with an emphasis on having good winter interest; they must have qualities of sustainability (i.e., be easy to grow, not require chemical pest management, and not represent a threat to native flora;) and they must be readily available. Some of them are “problem solving” plants for difficult areas.

This year’s winners of the Cary Award include a low-maintenance rose – Rosa ‘Knock Out’ and the native Yucca filamentosa or Adams Needle, joining 43 trees, shrubs, vines and ground covers that have previously been honored since 1997. A complete list, including information about and photos of individual winners can be found at www.caryaward.org. (Full disclosure: I have been a member of the Cary Award selection committee for many years as one of New Hampshire’s two representatives. Each New England state is similarly represented by professional horticulturists.) We have named future selections up to 2016, with each year’s winners announced at the appropriate time, and are working on plants to nominate and name for 2017 and beyond. Nominations may be made by anybody, and are not limited to those of the committee.

When considering which plants to replace those that may have been damaged in last year’s Halloween snowstorm, or which to choose to enhance your home or garden, be sure to start with Cary Award winners – proven for hardiness, reliability, ease and extended beauty.

Thursday, May 10, 2012

Native Plants and Others

It’s common knowledge that the state tree of New Hampshire is the white or paper birch (Betula papyrifera) while its state flower is the purple lilac (Syringa vulgaris.) The birch, venerated for its white bark and flexible but resilient “bend but don’t break” manner, is a hardy native, and one which stands out year round. The lilac, on the other hand, is decidedly “not from around here”, but rather an exotic species of southeastern European origin, having been brought by early settlers to Portsmouth, NH and then distributed far and wide. Despite its having existed in North America for over 300 years, it will never be a native, even though it has become naturalized (a term which is applied to both plants and people. In a way, most of us are all naturalized citizens.)  Its presence is often only revealed in spring, when its fragrant and familiar blossoms betray its position, one which once probably began in the dooryard of a colonial home long gone, its cellar hole a vestige of time past, as suggested by Robert Frost (another non-native – he was born in California) writes in his poem “Directive”:

...for the house that is no more a house,
But only a belilaced cellar hole,
Now slowly closing like a dent in dough. 

Lilacs, courtesy of April Walker
I compare the birch and lilac because they represent more than the official state flower and tree. They also illustrate the problem with declaring natives more suitable than exotics in the landscape.

Native plants (the definition of which varies, but typically used to describe those which were here before European colonization – but that is also problematic, as there were trees growing millions of years ago on this continent which are only found today in Asia) are thought to be better choices for the landscape, requiring less water and other care than exotics. There are plenty of Japanese Barberries, Norway Maples, Burning Bushes, and other plants which have escaped from cultivation and are now considered invasive species to disprove the thesis.

Let me state that I am a firm believer in the value of native plants, appreciate their beauty and status in the wild, and am a dedicated advocate for their use in managed landscapes whenever appropriate. Given the choice between a native and an exotic, I will typically opt for the former. However, as shown in the above example, exotics also have their place, so long as they don’t spread so aggressively as to displace native plants which have evolved along with native wildlife to their mutual benefit.

Drive down a country road when lilacs are in bloom, and you are likely to see lilacs growing as described by Frost, Whitman and others, an enduring and endearing shrub which has become an archetype many homeowners can’t live without in their gardens, despite its brief display. The white birch, on the other hand, is easy to spot at any time, but much harder to grow. It prefers cool, moist soil, and suffers when affected by drought. Indeed, its major nemesis is an insect called the Bronze Birch Borer which is able to detect a chemical signal emitted by birches under stress, and in which she lays her eggs which hatch and spell doom for the tree.

A similar example can be found with dogwoods: the native flowering dogwood (Cornus florida) is susceptible to another form of borer, as well as a destructive disease, when not grown under the right conditions. The exotic Kousa dogwood (Cornus kousa) is resistant to both, and is often the better choice. Hybrids between the 2 species (the so-called Rutgers types) have been produced which offer the best of both.

Clearly, the discussion of whether native plants are superior is complicated. Natives usually offer wildlife more value, and their presence in natural settings is critically important. However, it bears notice that natives may not always work well in managed landscapes, and appropriate choices may be found in plants which may not have originated here.

Tuesday, April 17, 2012

Azalea or Rhododendron?

Forsythias, those cheerful harbingers of spring (but certainly not the first woody plants to bloom) are completing their annual gaudy display, and as they fade into their seasonal greenness, our eyes fall upon the bright mauve-purple blossoms seemingly as common as Forsythia – the PJMs. These rugged evergreens with smallish oval-shaped leaves are thought of by many as azaleas, but they are not. They are Rhododendrons.

It is easy to understand the confusion, because they are related. All azaleas are Rhododendrons, but not all Rhododendrons are azaleas (they are botanically differentiated by the number of stamens each flower carries: azaleas have five, while Rhododendrons bear ten or more.) And azaleas are grouped within the genus Rhododendron, and part of the larger heath family which also includes heathers, blueberries and cranberries, mountain laurels, and more – all prefer cool, moist acidic soil, so mulches are always helpful (see my previous article.) Rhododendrons (not azaleas) can be divided into 2 categories: large-leaved and small-leaved types, and the PJM belongs to the latter group. Generally speaking, those with large leaves prefer some shade, although they flower better if given at least 1/2 day of sun, and the small-leaved Rhododendrons perform best in full sun, but tolerate some shade.

Those familiar with azaleas know them to bear bright red, pink, purple or white flowers on spreading bushes that remain semi-evergreen in the winter. These types perform better in more southerly locations, but can be found locally each spring when in bloom. They generally need careful siting to prevent the crisping of their foliage in our cold and dry winter air. Deciduous azaleas are far more reliable, and have a much greater range of flower color – from white to yellow, orange to red, but no blue or purple. And rather than having the narrow bloom times of the semi-evergreen varieties, by choosing different deciduous types, one can have flowers from April to August.

Rhododendron ‘PJM’ was hybridized in the 1930’s by the late Ed Mezitt of Weston Nurseries in Massachusetts, and he named it after the initial letters of his father, who founded the nursery. This fortuitous marriage of an Asian species and an American native has become the benchmark of hardy rhododendrons, and it is very hardy. It is also quite easy to grow, thriving in full sun to part shade. Its only downfall is soggy soil, as it leads to root rot. Indeed, its ease of growth has made it as common as lilac and forsythia in the northeast, and combines well with some Magnolias which bloom at the same time.

Because its purply color can be a bit jarring in the landscape, Ed Mezitt continued to breed rhododendrons in search of calmer pinks and whites, but also a true red (which he never achieved in his small-leaved hybrids, but came close with ‘Landmark’, one of my favorites.) The varieties ‘Olga Mezitt’ and ‘Aglo’ (Olga spelled backwards) are nearly as popular as the PJM, and bloom about a week or so later, nearly in concert with crabtrees. Their showy flowers are a clearer pink, but their habit is a bit more “open” than the denser ‘PJM’. These varieties, as well as many others including ‘PJM’ have deep green foliage that is aromatic when brushed against, and which turns dark bronze to mahogany when the colder weather arrives in the fall.

Mezitt’s breeding work also included azaleas, and he used the rich palette of deciduous species native to New England and the Northeast in his work, as well as a hardy semi-evergreen species from Korea. The deciduous hybrids are outstanding, because most bloom in early to mid-summer. (A future article will cover these superb “Summer Blooming Azaleas.”) Further reasons to grow these types: they are often sweetly fragrant, and many have vivid fall foliage, extending their season of beauty. Although his semi-evergreen introductions are less well-known (and hence not easy to find,) they generally perform better in central New England than those more commonly available, because that is where they were bred and tested.

Large-leaved Rhododendrons will soon be blooming in May. Although there are hundreds of varieties hardy for our area, most nurseries and garden centers stock relatively few. Because they are frequently used as “foundation plants”, it’s best to look for varieties which remain naturally compact, rather than dealing with green monsters which can quickly swallow up a window. Look for a discussion in an upcoming issue of some of the lesser-known varieties which I consider to be better in many respects from the traditional offerings.

Much Too Much Mulch

It’s officially Spring (after the winter that never was.) Gardeners and landscapers alike have been spreading mulches of shredded bark and/or wood chips around trees and shrubs and over emerging perennials, an annual event as regular as the swallows returning to Capistrano. Unfortunately, eruptions of mulch “volcanoes” are more predictable than the real things, as they are found an nearly every street and in every neighborhood. More about these in just a moment.

The widespread us of mulches is a relatively new phenomenon – shredded bark, which is removed from logs prior to their being milled or processed into pulp, was considered waste until the late ‘60’s or early ‘70’s, and it accumulated in massive piles surrounding lumber mills. If gardeners mulched at all, it was usually with peat moss, a less than perfect option for many reasons. Sometimes grass clippings would be used, or perhaps composted leaves.

Eventually though, a use for those piles of slowly decomposing bark was found, and a huge market was created – bark mulch. Because today’s log de-barking machines are even more efficient, it’s inevitable that some wood ends up in the mix, so bark mulch is less pure than it used to be. Somewhere along the way, an entrepreneur decided that inferior wood, old pallets, construction debris and the like (with no bark at all) could be chipped and ground up into small pieces, colored with dyes (brown, black, or red) and then sold as “bark” mulch. This product is inferior to the real thing, and should actually be called “colored wood chips”.

Using organic mulches (I’m leaving aside stone mulches for the moment) have many benefits, if properly applied. They help to modulate soil temperatures in cold or warm weather and slow down the evaporation of soil moisture. They help prevent soil-borne weed seeds from sprouting (but serve as a good incubator for those that land on the surface.) By offering themselves up as a food source, they help foster a healthy community of microbes which break them down by composting them into less complex substances that are released to the soil, increasing its nutrient and organic content as well as its tilth. Earthworms and other organisms are good recyclers of soil organic matter, which benefit plants even more. Further, microbes also become intimately associated with root hairs in the soil, and form an immense extension of a plant’s root system. Many plants cannot exist without these microbial populations.

However, if improperly applied, mulch can lead to plant distress or death. Over the past few years I have come to find that overmulching is a leading cause of plant death – especially of perennials. If you are applying more mulch yearly than is being broken down by the natural decomposition process, you are applying too much. Try to maintain an even layer about 2- or 3-inches thick from year to year. When mulches approach 4-inches in depth or more, they can actually repel water and reverse one of the benefits of mulch. If the surface needs to be refreshed, a very thin layer (sufficient to barely cover the ground and no more) may be spread, and never over the tops of perennials, for it can smother them over time.

Back to mulch volcanoes, those tall mounds of mulch around the trunks of trees and even shrubs. Where they originated is anybody’s guess, but the practice continues to be spread by uninformed landscapers as well as homeowners. Why are they bad? Bark respires by exchanging oxygen and carbon dioxide, and as mulches tend to hold excess moisture, they interfere with this respiration if piled against the trunk. Another consequence is the development of tree diseases which are favored in moist conditions. Follow nature’s model: walk through any forest, and you will not see the decaying leaf litter up against tree trunks. The natural flare of the trunk is clearly visible, and should be around your own trees as well.

As to what sort of mulch to use, I prefer the true aged (or partially composted) darker mulches, which have a softer and finer texture than more freshly-ground bark. I also like the dark color, as it resembles the color of soil and shows plants off well against it. I avoid the use of any mulches which are basically chipped and colored wood chunks – and especially those that are dyed red or orange to resemble true hemlock mulch (which, when fresh, is reddish, and is hardly ever available anymore.) I find this color disturbing in the landscape, but that is a personal preference.

I also like to use pine needles, shredded leaves and even compost in the garden whenever available. These are freely available and beneficial to the soil (and pine needles do not increase its acidity, despite popular belief.) “Weed barrier” fabrics do nothing to control the spread of weeds that originate from wind-blown seeds, and inhibit the growth and spread of desirable plants, particularly ground covers.

In any case, mulches should not be a dominant garden theme, but a helpful solution to make gardening easier while improving the soil at the same time. Vast barrens of bark mulch are often created and maintained, but do nothing to enhance the landscape. Even a meager lawn can look better, with scarcely more time needed to manage it. Dense plantings of shrubs, perennials and ground covers, topped with a light layer of organic mulch every other year or so, will require little mulch and maintenance over time – the best combination of beauty and function for today’s gardeners of whatever ability.