Blog

Is it spring yet?

For many gardeners, the earliest signs of spring are snowdrops, crocuses, and daffodils. But if you know where to look, you can find blooming flowers — and the little critters who need them – even before those bulbs come to life. One of the earliest bloomers in the Northern half of the US also happens to be one of our most interesting and valuable native shrubs: Salix discolor, or the amazing Pussy Willow!

In February, Pussy Willows are already producing the adorable, fuzzy flowers that give them their common name. This type of flower has no petals or fragrance, and is known as a “catkin” from the Dutch word “katteken,” which means kitten. Just as soft to the touch as they look, the silvery catkins are popular in spring flower arrangements and delight children of all ages.

Over the next month, the catkins will gradually open revealing numerous string-like filaments. Pussy willow shrubs are dioecious, meaning the shrub holds either male or female flowers. On the male plants, the filaments hold quantities of pollen that give the catkins a bright yellow appearance. The female flowers look more like spiny caterpillars than kittens, so for ornamental purposes, the male shrubs are preferred.

Pussy Willows typically are large, multi-stemmed shrubs or small trees, topping out between 15 and 25 feet. Unlike most trees, however, they can benefit from being severely pruned, or “coppiced,” to keep them shorter. Cutting back the branches after blooming will generate multiple slender new stems, increasing the fullness of the shrub and the number of catkins within easy reach in the following season. 

Humans have used the flexible young branches of willows for basket-weaving, arrows, rustic fencing, and many other purposes for hundreds of years. One of the most important traditional uses of willow bark was medicinal. Willow bark tea contains salicin, a pain-killer and fever reducer, now synthetically produced as aspirin.

By far the most important use of Pussy Willow in our gardens, however, is to support native pollinators and other insects. As one of the very earliest plants to bloom, Pussy Willow provides nectar and pollen for early-emerging native bees. In fact, the Andrina family of native bees are willow “specialists” – they must have willow pollen to feed their young. The nectar of willow catkins also supports many other insects in early spring when food is especially scarce.

All summer long, the leaves of Pussy Willow feed the caterpillars of more than 450 species of moths and butterflies — second only to oak trees in providing caterpillars for baby birds! Willow is a host plant for a huge number of our most spectacular butterflies: Viceroy, Red-spotted Purple, Mourning Cloak, and various hairstreaks, fritillaries, and dusky-wings.

In addition to Pussy Willows, there are at least 90 species of willows native to the US, and 20 or more native to the Northeast. Unfortunately, there are also many non-native species sold in the nursery trade, including the well-known weeping willow (Salix babylonica), that do not provide the same value to our native birds and insects. Be sure to check the scientific name before you add a willow to your landscape.  Pussy Willow (Salix discolor), Black Willow (Salix nigra), Shining Willow (Salix lucida), and Silky Willow (Salix sericea) are all good native shrubs, but Pussy Willow is likely the easiest to find.

Pussy Willow is a great choice for sunny wet areas, including rain gardens. It is an ideal solution for a soggy lawn area where rainwater tends to collect. All willows have extensive root systems that seek out water, so they should not be planted near a septic system, but they are perfect near a stream or pond or anywhere you want to stabilize a slope eroded by stormwater.

Deer will browse Pussy Willow, but because the shrub actually benefits from winter pruning, the nibbling is unlikely to harm the plant. Pussy Willows grow fast and are very resilient. In fact, many people propagate them simply by cutting off a dormant stem in winter and sticking it in the ground, or even a glass of water, until roots appear. Hardy in Zones 2 through 7, the only thing Pussy Willow does not tolerate well is shade. You’ll need at least a half day of sun, and plenty of water until the roots are established. 

Pussy Willow is an all-around winner: easy to grow, interesting and attractive, incredibly valuable for the ecology, and a real problem-solver for a troublesome spot in the landscape.

So, where will you put it?

THIS BLOG IS AUTHORED WEEKLY BY CATHY LUDDEN, CONSERVATIONIST AND NATIVE PLANT EDUCATOR; AND BOARD MEMBER, GREENBURGH NATURE CENTER. FOLLOW CATHY ON INSTAGRAM FOR MORE PHOTOS AND GARDENING TIPS @CATHYLUDDEN.

TO SUBSCRIBE TO THE BLOG – AND NOTHING ELSE – ENTER YOUR EMAIL BELOW

Many of us grown-ups, upon learning of the complex relationships between native plants and insects, wonder “why am I hearing about this for the first time?” or “did I miss this in school?”  No worries! You are not alone. This subject only recently has become part of the basic biology curriculum.

At the Greenburgh Nature Center, we want people of all ages to understand this vital relationship. So, let’s start at the beginning — with some visual aids!

“Native” plants are the species that evolved in a particular place without human intervention. In the US, that means the trees, shrubs, grasses, and perennials that were here before European settlers arrived. Native plants are important largely because of their relationship with native insects. 

The majority of insects eat plants. Most other animals, including humans, also eat plants, or they eat other animals that eat plants. As the main food supply for most living things, plants would soon be wiped off the face of the Earth if they did not develop strategies to protect themselves from all of these plant-eaters!

Over the millennia, plants evolved defenses to protect themselves from plant eaters. You may recognize a few of these if you’ve eaten a very hot chili pepper or had a bad reaction to touching poison ivy. Insects (the largest category of plant eaters) face similar problems.

To survive, insects had to evolve methods of overcoming plant defenses. But the enormous variety and complexity of defenses in the plant world limited insects to overcoming only the specific defenses of a limited number of plant families. As a result, about 90% of all plant-eating insects are “specialists,” meaning they are able to eat only a few closely-related species of plants. Those plants became the “host” plants for the insect species adapted to overcoming their specific defenses.

The best-known example of this insect/host relationship is the monarch butterfly and milkweed. Milkweed has sticky sap loaded with toxins that repel most insects. The monarch caterpillar evolved the ability to tolerate those toxins, but has no ability to overcome the defenses of other plants. Monarch caterpillars cannot eat the leaves of plants outside of the milkweed family.

The situation is the same for most plant-eating insects. These evolutionary plant/insect relationships developed over very long stretches of time, thousands of years. So, most insects can eat only those plants that evolved with them in the same place and over the same long period of time. That is why insects native to North America cannot eat plants that have been brought in, or “introduced,” by human settlers from other continents.

As you look around your neighborhood, you will no doubt see many plants introduced from other continents: Norway maples, Korean dogwoods, Japanese maples, Norway spruces, Japanese barberry, English ivy, Chinese feather grass, and many more. These non-native plants have evolutionary relationships with insects on other continents, but most North American insects cannot eat them. Many of these plants are marketed as “pest-free” for exactly that reason. Insects here avoid them, and many gardeners like that! 

But “pest-free” plants come at a terrible cost: nearly all (96%) of our native terrestrial birds need insects to feed their young. Well-documented and shocking declines in insect and bird populations over the past 50 years tell us we are facing a crisis. Without native plants, we lose insect populations. Without insect populations, we lose birds. We also lose all of the other animals that feed on insects, as well as butterflies, fireflies, and specialist bees that pollinate food crops and most of our flowering plants. More broadly, without native plants, biodiversity itself is threatened and our ecosystems become unstable.

Fortunately, this is one crisis we can solve in our own yards. By choosing native plants, and planting a lot more of them, we can actually bring insect species back from the brink of extinction!

A wonderful example of this is the story of the beautiful Atala butterfly, native to parts of Florida. The Atala was believed to be extinct from 1939 until the 1960’s when a small population was discovered on an undeveloped island off the Florida coast. Then, in the 1980’s, horticulturists discovered and began growing a lovely small plant called the Coontie palm (Zamia floridana or integrifolia). Coontie was once common in Florida, but it was overharvested in the wild by early settlers for its starchy root. By the 1930’s, the plant had largely disappeared from the Florida landscape. Beginning in the late 1980’s, the re-discovered Coontie became popular with homeowners and was planted in gardens and along walkways in many Florida suburbs. And suddenly, the Atala butterfly re-appeared!

It turns out that Coontie is the host plant for the Atala butterfly! As Coontie became popular in suburban yards, the Atala butterfly rebounded. Today, this beautiful butterfly is common enough that some misguided homeowners look for pesticides to control the Atala caterpillars eating their Coontie plants!

So, hopefully, we adults are now on common ground with today’s kids. We understand that native plants are a key element in the health of our planet. If we continue to use “pest-free” non-native plants, we will continue to see our favorite back-yard birds disappear, along with monarchs, other butterflies, and the rest of the natural food web. Or, we can do a simple good thing for nature: fill our yards with native plants and provide the food so critical for life.

THIS BLOG IS AUTHORED WEEKLY BY CATHY LUDDEN, CONSERVATIONIST AND NATIVE PLANT EDUCATOR; AND BOARD MEMBER, GREENBURGH NATURE CENTER. FOLLOW CATHY ON INSTAGRAM FOR MORE PHOTOS AND GARDENING TIPS @CATHYLUDDEN.

TO SUBSCRIBE TO THE BLOG – AND NOTHING ELSE – ENTER YOUR EMAIL BELOW

Conservationists, ecologists, and this blog repeatedly urge gardeners to use more native plants. Native plants are essential to a healthy ecosystem because they are the first link in the food chain. Insects native to a particular region generally cannot eat plants from other regions, and insects are the primary food source for birds and many other animals. We know that insect and bird populations are declining rapidly, so we ask homeowners, residents, and property managers to replace lawn, which has no ecological value, with abundant plantings of native trees, shrubs, grasses, and perennials. 

But not everyone can do that. Gardening is not everyone’s hobby and, for many people, taking care of a lawn and a few shrubs is really all they can manage. So, what if you want to help save songbirds, butterflies, and fireflies, but transforming an entire landscape to native plants is not an option? 

In a recent interview, Dr. Douglas Tallamy, research scientist and best-selling author of several books about the interaction between native plants and insects, was asked whether there are any simple things that anyone with a yard can do to benefit insects and birds. He immediately responded, “Plant an oak tree.”

Planting a native oak tree — or saving one — may be the single most valuable thing you can do to support nature. Oak trees are “keystone” plants, which means they are essential to the survival of many other species. Without them, there would be a cascade of species extinctions.

The importance of oaks to our native birds is perhaps the most dramatic example. Virtually all songbirds need insects to feed their young. Baby birds cannot eat seeds or berries. They must have insects, especially caterpillars. Caterpillars, the larvae of moths and butterflies, are soft, easily digested, and loaded with the nutrition baby birds need. Dr. Tallamy’s research has shown that a pair of Black-capped Chickadees needs 7,000 to 9,000 caterpillars to raise a single clutch of 3 baby chicks to maturity. Chickadees are very small birds and, if there is enough food, they can raise 2 clutches of babies in a season — that’s a lot of caterpillars! All of our other backyard birds have the same needs. Adult birds spend all day finding and transporting thousands of caterpillars to their nests. And where is the best place to find all those caterpillars? On the leaves of native oak trees!

Oak trees are caterpillar factories. Over 500 species of moths and butterflies lay their eggs and hatch their caterpillars on native oak trees. By comparison, not one single species of North American moth or butterfly caterpillar can mature on the leaves of a Norway maple! In fact, none of the popular non-native trees typically planted in suburban yards help birds feed their babies. Japanese maples, crape myrtles, Korean dogwoods, Norway spruces, Callery pears, and Kwansan cherries are essentially “barren” – they do not support caterpillar populations or other insects of value to birds. 

Planting a native oak tree, or saving one from destruction, is an easy way to support biodiversity. There are over 90 species of oaks native to the US, and many of them are widely available, hardy, easy to care for, and very long-lived. In the Northeast, white oak, red oak, scarlet oak, burr oak, pin oak, and black oak are all good choices.

And you don’t need a big property to have a happy oak tree. Although an oak can reach 100 feet tall with a crown spread of 120 feet given a couple hundred years, planted in an average-sized lawn, 20 or 30 feet from house and pavement, an oak can live its long life without causing any problems. The roots of oak trees tend to run deeper than most trees, so they are less likely to buckle your driveway or sidewalk than many other species. And oaks make great specimen trees in lawn areas because they typically have a more open canopy than maples or other big shade trees. They allow enough sunlight through to permit lawn (or native groundcovers) to grow underneath.

Oaks do best in full sun, and average, well-drained soil. Young trees will need regular watering until their roots are well-established, but once established, oaks need very little care. Professional pruning in the first decade will assure healthy branching, but supplemental water and fertilizer is rarely needed. 

It is easy to add an oak tree to any landscape because the best practice is to start small. Transplanting a large oak can be expensive and problematic. Oaks devote most of their early life to developing the root system that will keep them healthy for several hundred years. Large specimens from nurseries have been severely root-pruned to make transplanting possible, but the loss of root structure also makes them more vulnerable to transplant shock. So, starting with a small tree, or even a sprouting acorn, is inexpensive and likely to produce the healthiest tree in the long run. In just a few years, a young sapling will catch up to a severely root-pruned specimen and surprise you with how fast it grows!

So, do this one thing. If transforming an entire landscape to native plants is not an option, consider planting a young oak tree. If you have a lawn, you already have a good spot for the most valuable keystone plant there is. 

Plant an oak tree!

For further information, read the fascinating book The Nature of Oaks by Douglas W. Tallamy

To subscribe to the blog – and nothing else – enter your email below