Monday, March 30, 2015

Magnificent Magnolias

Morris Arboretum has 166 magnolia plants representing 79 different kinds of magnolias planted in the public garden (35 additional plants which include 7 additional kinds of magnolias are on the Bloomfield Farm side).

Interested in adding magnolias to your garden? The start of April is a good time to select and plant magnolias. A favorite variety is a butter-yellow flowering variety called Magnolia Elizabeth. This relatively new hybrid does best in full sun but tolerates light shade. It grows fast and will eventually become a big shade tree. Other brighter yellow forms will soon be coming on the market but the paler forms combine better with the other pink and lavender magnolias.

Magnolia Elizabeth was bred to bloom later than most magnolias and therefore is more likely to miss a late frost which sometimes kills the flowers.

Magnolias are available from better garden centers and from specialty mail order nurseries.

Photo: Paul Meyer

Photo: Judy Miller
Photo: Judy Miller

Friday, March 27, 2015

Rejuvenative Pruning of Mature Shrubs

by Anthony S. Aiello, The Gayle E. Maloney Director of Horticulture and Curator

If you are like me, you never have enough time to accomplish all of your gardening tasks throughout the year, and eventually those well-behaved shrubs in your garden grow beyond their desired size and start to crowd other plants in the garden. The beauty of growing and pruning deciduous shrubs is that they can be maintained at a desired size through rejuvenative pruning.

The first thing to keep in mind when pruning shrubs is to have the proper (and properly sharpened) tools. These will include a good pair of hand pruners, a pair of loppers, and a hand saw. When it comes to hand pruners, I prefer a good pair of bypass, or scissor pruners, that make smoother and cleaner cuts than anvil type pruners. There are a range of pruning saws available, and again the most important aspect is to have a saw that is specifically designed for pruning and is fitted with a good, sharp blade.

The second most important aspect of pruning is appropriate timing, and this is based on when the plant flowers. Spring flowering shrubs are those that flower before June 15th. These plants set their flower buds on new growth in the previous growing season, and so they should be pruned soon after they flower. Examples of spring flowering shrubs include lilacs, azaleas, and forsythia. Summer flowering shrubs are those that flower after June 15th and set their flowers on new growth formed during the same season. This group includes chastetree (Vitex), bluebeard (Caryopteris), and crape myrtle and these can be pruned in spring, before flowering.

There are many different methods and techniques of shrub pruning, but most overgrown shrubs can be completely rejuvenated in two to three years. The first step is to remove any dead or crossing shoots; after this, prune out approximately one-third of the oldest shoots at the ground. Remove overhanging branches that shade out the lower portions of the plant and tip-back any leggy young shoots. If you repeat this process for three consecutive years, you will have completely rejuvenated your shrub, with the end result being a more robust, healthier, and floriferous plant.

So start thinking now about which of your shrubs could use some pruning this spring, and don’t worry when it comes time to get started. The beauty of shrubs is that they are a lot like dogs – they are very forgiving and they always come back with enthusiasm.

To learn more about pruning, join one of our upcoming horticulture classes.

Wednesday, March 25, 2015

Spring Tasks: Lawn Seeding

The last week in March is a good time to over seed bare patches in the lawn.

Tips for getting started:
  • Using a garden cultivator or iron rake, scratch the soil surface to provide a seed bed. 
  • Sprinkle the seed over the prepared area and gently tamp in the seed using the flat end of the rake.
  • For fine lawns use a mix of Kentucky blue grass varieties, for high traffic sunny areas, use the fine leaf forms of tall fescue.
  • We prefer not to fertilize lawns in the spring because it induces excessive growth and it can lead to disease problems later in the spring.  If you must fertilize, do so lightly and with a slow release organic form.
  • The first mowing of the spring should be short to clean up debris.
  • Thereafter, mow high, at lease 2-2 ½ inches to encourage deep roots and a drought resistant lawn.

Monday, March 23, 2015

Spring Tasks: Dividing Perennials

Late March is a good time to divide perennials like Chrysanthemums, daisies, black-eyed susans and Daylilies.

Why divide plants? 
Dividing perennials serves to rejuvenate the mother plant and provides more for your garden and for friends.

How to Divide

It's important to dig carefully with a digging fork.
    •    Lift and gently shake
    •    Using the fork, insert through the center of the clump.
    •    Take a second fork and insert it back to back with the first and pry the clump apart.  For larger clumps repeat.

    •    Replant what you need and give a friend the rest!
    •    When replanting, work the soil first and plant at the same level that it was before lifting.

Some perennials like daisies and lambs ear require division every 2-3 years or they loose vigor and decline.

Friday, March 20, 2015

5 Heralds of Spring

Happy First Day of Spring!
Signs of the season are popping up everywhere around the Arboretum. Here are a few of our favorite surefire signs of spring. How many have you spotted?

1. Crocus tommasinianus (crocus) and Galanthus (snow drops)
Photo: Paul Meyer

2. Eranthis hyemalis (winter aconite)
Photo: Paul Meyer
 3. Robins
Photo: Susan Marshall
4. Hellebores
Photo: Paul Meyer
5.  Willows
Photo: Paul Meyer

Wednesday, March 18, 2015

Early Spring Round-up

With the official start of spring just around the corner, it's time to trade the snow shovels for garden spades! Here is our early spring round-up for tips to get you prepared for garden season:
  • Start your seeds indoors.
    Our horticulturist, Louise Clarke has some quick tips for getting started. Read more...
  • Get to know your site. The best landscapes come to life when plantings match the site's characteristics. Check out this useful video for inspiration. Prefer more hands-on guidance? Learn from an expert at this workshop with former Brooklyn Botanic Garden Horticulture Educator, Charles Mazza.
  • Brush up on your pruning skills. We know it can be exciting to see our yards come alive with leaves and new shoots each spring, but before you know it things can get a little, well, Gray Gardens... Learn proper pruning techniques before the bushes get a chance to take over. When purchasing a new plant, ask your nursery how to care for it or take a local workshop like this one on Pruning for the Homeowner.
  • Kick it up a notch.
    Already a savvy gardener? Elevate your plant knowledge by taking a botany class. This one on fungi is a great place to start.

Monday, March 16, 2015

Gardeners, start your seeds!

The snow is melting, and even though it's too wet to work in the garden soil, it's time for gardeners to sow seeds indoors. Get a jump start on the growing season by sowing now.  

Before you start, here are some good things to know:
  • Our region's (mid-atlantic) last frost date is  approximately May 15, so read your seed packets to determine when to start your seeds. Check the Farmer's Almanac for your region's last frost date.
  • Some seeds are better sown directly into the soil, like radishes, but many others will appreciate the head start indoors like tomatoes and peppers. Try this handy growing calculator to learn more about timing seeds.
  • Don't forget seeds are a great way, sometimes the only way, to grow the more unusual vegetables and flowers you won't find at the local garden center or big box store. 
  • Sowing seeds is a wonderful way to introduce children to the joys of gardening and give them an appreciation of where food comes from.  
Spring is just around the corner, sow get busy!

by Louise D. Clarke, Morris Arboretum horticulturist

Monday, March 9, 2015

3 Steps to Big Beautiful Roses

  1. Prune! Now's the time to start pruning your repeat-blooming roses: hybrid teas, floribundas, and modern shrub roses. An easy rule of thumb is "Prune when the forsythia bloom." If you have species or old garden roses, wait until after flowering to prune, or else you'll cut off their spring blooms.
  2. Feed After pruning your roses, give them a boost with organic fertilizers. Compost, manure, blood meal, kelp meal, and fish emulsion are just some of the great nutrient sources your roses need for big, beautiful blooms.
  3. Deadhead After your roses have started to bloom, keep up on deadheading to keep your repeat-flowering roses looking great and blooming all season long.
Want your roses to be the envy of the neighborhood? 
Join our upcoming class, Rose Pruning Basics, for even more great tips! Register Now

Saturday, March 7, 2015

Mulch Matters

Photo: Arnold Winkler 
 by Louise Clarke, Horticulture Section Leader, Bloomfield Farm  

Gravel, river rocks, seashells, tumbled glass, and shredded tires can all been used as mulches, some of which have decorative as well as functional uses. Any material that is applied to the soil’s surface as a covering is considered mulch, but organic mulches are especially beneficial to the garden.

In addition to helping retain soil moisture, controlling erosion, moderating soil temperature and suppressing weed growth, organic mulches such as shredded bark, leaf mold, and pine straw provide the additional benefit of decomposing into soil-enriching humus. Humus builds soil structure and increases its capacity to hold nutrients and water.

With the advent of colored organic mulches, gardeners now have a rainbow of choices. Is colored mulch safe for your family, pets, and plants? That depends. Dyes are typically vegetable or mineral-based and are nontoxic; iron oxide (rust) is used to make red mulch, and carbon black (think charcoal) is used for dark mulch. However, the source of the wood used to manufacture mulch can be more troubling. Wood is recycled to create mulch, but unscrupulous recyclers may grind chromated copper arsenate (CCA) treated wood, which is commonly used to build rot-resistant decks and play equipment. CCA-tainted mulch can leach arsenic, a known carcinogen, into your soil. Hmmm, anyone for arsenic-laced tomatoes?

When buying bagged mulches, look for a certification seal on the bag from the Mulch and Soil Council (MSC). Big box retailers and independent garden centers stock MSC approved mulches. Founded in 1972, the MSC is a national non-profit trade association that has developed product certification programs for potting soils and mulch. See http://www. for more information. Mulches that display the MSC seal have been tested and found free of CCA. There is no risk of CCA contamination if you know that your mulch is sourced from raw lumber. If you employ a landscape contractor who delivers bulk mulch to your property, be sure to ask if they know the source and the components of the mulch being used.

Now that you’ve selected the mulch for your garden beds and trees, are you or your landscape professional applying it correctly? Take a walk in the Arboretum’s Widener Woods to see how Mother Nature mulches; the optimal depth of organic mulch is two to three inches. Excessively thick mulch application results in decreased air circulation and water-logging, which encourages root rot diseases and provides cozy homes for bark-chewing rodents. The ever popular “mulch volcanoes” applied to trees (often seen at apartment complexes and shopping centers) lead to disease and injury which shorten tree life spans. Shrubs that have shallow roots like azaleas and boxwoods, as well as some trees, will grow new roots upward into thick mulches to avoid suffocation, but potentially risk drying out and will decline as mulch decays.

As an integral component of home landscapes, mulch provides beauty and benefits to shrubs and trees when applied and maintained in a responsible fashion. Organic or inorganic, colored or natural, choose and apply wisely for optimal plant health.

Learn more at one of our upcoming Landscape Design classes.

Friday, March 6, 2015

5 Fun Facts about Fungi!

Fungi are some of the most overlooked organisms, despite making up 25% of the world's biomass and having an estimated 1.5 to 5 million species on Earth.

Did you know...
  1. Fungi are more closely related to Animals than to Plants
  2. Only 2-6% of all fungi on Earth have been discovered and named
  3. 95% of all plants rely on fungi for efficient nutrient uptake
  4. Bakers yeast is a fungus and a distant cousin of truffles
  5. Fungi don't require sunlight to grow
Intrigued? Learn more in our upcoming class, Fungi and Plants: A Love-Hate Relationship, on April 28, 2015.  Register Online Today