Recently my inbox has been overflowing with questions from readers worried about the abnormally warm winter we’ve been experiencing. Many of the questions center on daffodils; in particular, what to do about unruly bulbs. Before replying, I first spoke with a few local nursery experts to gain their advice. Here are five of my readers’ top concerns about daffodil bulbs and what to do about them. Continue reading →
Why wait for spring when you can savor it in winter? Forcing flowering trees and shrubs to bloom is as easy as 1-2-3. All you have to do is cut a few branches, bring them indoors and follow the instructions below. Continue reading →
Given my preference for long days spent in the garden, December 21 is always cause for celebration. That’s because from that point forward every day will get just a little longer. And with the return of the light, my mind is filled with thoughts of the garden and plans for what the New Year will bring. Continue reading →
Most of us know not to plant watermelons in the mountains or aspen trees at the beach. But when it comes to the countless plants available at the nursery, things can get murky. That’s when a handy tool called the USDA Plant Hardiness Zone Map can make all the difference. Not only can it tell you what plants will survive where, but it can also ensure a year’s worth of success in the garden. Continue reading →
Just the other day, I was working with a bunch of Master Gardeners preparing a garden for the county fair when one of them noticed a bare space. Sure enough, in one of the central beds, a group of plants had recently given up the ghost on a prominent corner. In no time, we all agreed that a lacy evergreen would be the perfect replacement. And that’s when I suggested chamaecyparis. Continue reading →
Recently I published a blog post about bees, wasps and hornets. To add interest to the story, I created a graphic featuring 4 common species and asked my readers to identify them. One reader labeled three of them correctly and labeled the fourth one ‘jerk.’ (Actually he used more colorful language, but this is a family blog). That ‘jerk’ was the yellow jacket. Continue reading →
Most flowering plants need lots of sun to keep on blooming. Still, over time, the blooms often start to diminish. That’s where deadheading can make all the difference. Not only does it keep plants looking neat, but it also promotes new growth and re-flowering. And, there’s nothing quite like getting a plant to re-bloom that otherwise looks done for the season.
WHAT IS DEADHEADING?
Simply put, deadheading is the practice of removing spent (dead) flower heads from a plant.
Dried poppy seed heads
All plants follow the same life cycle; that is, they grow, produce flowers, set seeds and die. No sooner do the blooms fade, and a plant turns its energy to setting seed. That said, by removing spent blooms, you can delay production of seeds. This in turn redirects energy to flowering. The result is a healthier, more vigorous plant that blooms for a longer period of time.
HOW TO DEADHEAD
Regular deadheading benefits all blooming plants. However, the world of flowers is diverse and many species require their own specific methods. Here are tips on how to deadhead six key types of flowering plants:
Clusters of flowers with leaves on their stems
Purple garden phlox
These types of flowers include tall, leggy plants like phlox, yarrow, daisies. To keep your plant looking neat, remove the spent flowers just before they die back completely.
A good rule of thumb is to reach into the plant and prune the spent flowers back to the first or second set of leaves. This not only helps hide the cut, but it also encourages the plant to bush out as it produces new blooms. I vary the lengths at which I cut to keep the plant shapely.
Flowers with no leaves on their stems
Long-stemmed orange daylily
Flowers like daylilies and hostas have no leaves on their stems. Cut the entire stalk back to the base of the plant once it has finished flowering.
Multiple flower spikes of salvia make pruning tedious
Once the initial flush of flower spikes start to brown, salvias look like they’re done for the season. With proper deadheading, however, you can encourage them to keep on blooming.
What may at first glance look like a single flower stalk is actually three flower stalks growing together – a central stem surrounded by two, smaller ones on either side. As soon as the central stalk starts to wither, remove it. This will encourage the side shoots to grow. Then, once the side shoots lose their color, cut them off too.
Deadheading salvias in this way can encourage the plant to re-bloom at least twice and sometimes three times during the season, especially if you feed it mid way through the summer. Try one of these stunners for great summer color: Salvia patens Cambridge Blue, bright red SalviaJezebel, or the traditional purple/blue favorite Salvia x sylvestris May Night.
Bushy plants with small flowers
Bushy perennials like coreopsis can be encouraged to produce a second round of blooms way past their typical flowering time.
However, it can be tedious deadheading so many tiny flowers. Instead, I grab big chunks of spent blooms in one hand and shear them back with a pair of long-blade shears in the other. This not only encourages the plant to re-bloom a week or so later, it keeps thinks looking tidy. Try soft yellow Coreopsis Moonbeam for reliable blooms all summer.
With roses, the number to know is ‘5’
Most of us know that roses need to be deadheaded to flourish. Remove withered blooms by pruning back to above a five-leaflet leaf, cutting on an angle.
Geraniums need consistent deadheading to look their best
All annuals need to be deadheaded regularly to thrive (with the possible exception of begonias, in which case you should prune the leaves.) Popular annuals like geraniums and petunias must be constantly snipped, pinched or cut back to keep flowers looking neat and to encourage blooming. For a more in-depth tutorial on how to prune these annuals, click here for How To Keep Your Potted Plants In Shape All Summer.
Butterfly weed is a prolific self-seeder
Some flowers, like columbine, echinacea and butterfly weed are prolific self-seeders. If you’re looking to produce lots of new baby plants, leave the seed heads on and they’ll quickly spread around your garden.
DEADHEADING WON’T DAMAGE THE PLANT
It’s rare to damage a plant by cutting it. Use common sense while removing spent flowers, taking care to hide your cuts under existing foliage. Remember to sterilize your pruners regularly to prevent spreading disease between plants. You’ll reap the rewards of a new flush of blooms!
Looking for garden design ideas? I post photos of my landscape projects on Instagram.
Warm weather is back and many of our plants are bursting into flower. But as we celebrate, there’s another less attractive family of plants springing into life as well. These are the dark cousins of our ornamentals: the perennial and annual weeds. The bane of all gardeners, they stubbornly return each year, unfazed by our attempts to remove them. Continue reading →
Trees are generally admired for their surface beauty, but their health and vigor springs from what’s underground. That’s according to Dr. Kelby Fite, Director of Research for Bartlett Tree Research Lab in Charlotte, NC. Recently, he spoke to Maryland’s master gardeners on the reasons why trees fail.
Fite’s lecture entitled ‘Managing the Landscape Below Ground’ provided a wealth of information about how to improve the life of the trees in our landscape. According to Fite, it all starts with the soil.
“We are all guilty of fouling up the soil,” he said. “But, it’s far easier to preserve soils than to remediate after they’re damaged.”
Before reaching for the fertilizer, Fite advises digging a little deeper into the source of the problem. Following are five common reasons why trees fail and what to do about them.
COMPACTED SOIL LEAVES NO ROOM TO BREATH
When it comes to tree health, nothing hurts a tree more than compacted soil. Often caused by construction, soil compaction strikes trees at their roots, depriving them of essential water, oxygen and other nutrients. It also makes it harder for a tree to anchor itself.
Compacted soil makes tree anchorage difficult
Compaction occurs when soil particles are compressed by external factors such as mechanical or human traffic, resulting in reduced pore volume. Since there is less space for air and water, these types of soils have reduced rates of water infiltration and drainage and are often hydrophobic (meaning the water runs off).
In the case of a tree, this leads to poor growth, higher water needs and increased susceptibility to pests and diseases. It is also one of the primary reasons why trees fail.
Fertile, aerated soil
Compacted clay soil
Think of soil as a sponge, with large and small particles.
“What happens when we squeeze a sponge?” Fite asked. “We are increasing the amount of solid matter.”
Tree roots are extensive, and with the exception of the taproot, located for the most part just 8 to 10 inches below the soil. They need space to grow. With compaction, however, many trees will never develop a taproot, instead establishing a network of weakened lateral roots that are unable to keep the tree vertical.
Meanwhile at the soil surface, the tree’s fine feeder roots (which under ideal conditions can extend 4 to 7 times the drip line of the tree) are compromised, too. This reduces its ability to absorb water, oxygen and nutrients.
SOLUTION: Build away from a tree’s drip line and keep mowers and other machinery off of the soil. For existing trees under stress, add a mulch circle. (More on that below.)
DEPRIVING TREES OF FALLEN LEAVES
This is a tough one. I’m not sure I’m ready to shred my leaves and scatter them all over the lawn. But think about it. We spend time and money to rake up and dispose of one of our plants’ most important source of nutrients. Then we go to the store and buy it back again as mulch or soil additives.
“It’s not a great business model,” said Fite.
According to Fite, we are removing one pound of nitrogen per 1000 feet just by removing the leaves from our properties. This is a big loss for trees as well as other plants. And this doesn’t even take in to account the fossil fuels burned to operate leaf vacuums.
Our soils are low in organic matter because we don’t allow leaves to decompose like they do in the forest. When left alone, leaves return nitrogen and other organic matter to the soil. They also protect the soil surface, adding to its water holding capacity. And as they break down, they provide porosity and aeration, allowing more water to infiltrate the earth.
Shredded leaf mulch
SOLUTION: Shred your leaves with a mower and make leaf compost or leaf mold mulch (not the same thing.) For some great info on how to do both, click here for the spruce.com’s excellent article Rake Leaves and Make Compost Mulch.
HIGH pH SOILS ARE BAD FOR TREES
In a perfect world, soils have a slightly acidic to neutral pH (a pH of 5.5 to 6.5). Urban and suburban soils, however, often contain debris left behind from construction. This generally results in a higher soil pH due to leeching from masonry walls and foundations. Moreover, irrigation water frequently has a higher pH, too.
Leeching from masonry leads to soils with higher pH
All of this can lead to a dramatic difference between the nutrient ability of your native soil and that affected by construction and other materials. Since developed soils tend to have a higher pH and modified temperature, they put more heat stress on plants. As a result, trees grown in these locations may show signs of nutrient deficiency (like yellowing of leaves) and take longer to establish. They may even fail.
SOLUTION: Do a soil test to determine the pH and get the turf out from under your trees. Lawns may thrive on alkaline soil (that’s why we add lime), but trees prefer a lower pH.
Mulch improves soil structure while providing protection to a tree’s roots. It also supplies organic matter to the soil that reduces compaction. And it moderates soil temperatures, conserves moisture and eliminates competition from grass. Yet, many landscape trees are planted out in the lawn with no protection. This is another reason why trees fail.
Fite recommends mulching out to the drip line of a tree if you can. It will help prevent ‘mower blight’ (or your mower banging into the trees) and also protect against stripping from string trimmers. Mowers, by the way, also contribute to soil compaction, especially when they’re operated in wet conditions.
Mowers contribute to soil compaction and can damage a tree
SOLUTION: Create a mulch circle around your trees. It will help protect them from mower damage. And as the mulch decomposes, it will aerate the soil and provide nutrients.
FERTILIZING FOR NO REASON
According to Fite, fertilizer doesn’t fix everything. Pull a soil sample from around your tree first to determine whether or not to fertilize. Most soil labs will run diagnostics on your sample and send you back a prescription for what to add to your soil to improve its composition.
Before fertilizing, take a look around the landscape. If construction has occurred and interrupted a tree’s root zone, no amount of fertilizer is going to fix the problem.
And remember, although native soil usually contains lots of organic matter, during construction this layer is often buried under layers of sand or debris. Or sometimes, it’s stripped off entirely. No amount of fertilizer is going to bring life back to this kind of soil.
SOLUTION: Do a soil test to find out what your soil is made of before reaching for the fertilizer. Fix the soil first, then use fertilizer to adjust accordingly.
OTHER THINGS YOU CAN DO TO HELP YOUR TREES
Fite offered a couple additional suggestions for how to get your trees back in shape (assuming you haven’t destroyed most of the root system by building too close):
INVIGORATE THE ROOTS
Many times the best thing you can do for your trees is to invigorate their roots. Bartlett Tree uses an air spade, a tool that generates a high velocity jet of air to dislodge the soil. The rush of air breaks up and ‘tills’ the soil without removing it to a depth of about 8’ (the depth of the feeder roots). This method of improving the soil leaves root systems intact.
The air spade was originally developed by the military to clear land mines. Nowadays, it is used by landscapers and arborists to invigorate roots. After the soil is excavated, add soil, compost and mulch to settle the soil back down. Then water the tree.
Mulch breaks down because the microbes eat it for carbon, resulting in it having to be replaced every year. Charcoal, on the other hand, is stable, meaning it lasts for centuries. Biochar is a fine-grained, highly porous charcoal that is added to soil to help it retain water and nutrients. It acts like a dry sponge, but on its own contains no nutrients. Bartlett Tree recommends blending it with compost for best results.
Biochar acts as a dry sponge, but contains no nutrients
“Put the two together and magic happens,” said Fite.
Buyer beware, though, biochar is not regulated, so buy from a reputable source and read the label carefully.
Kelby Fite, Ph.D. is a VP and Director at Bartlett Tree Research Lab.
When kids can’t get along, parents know it’s time to divide them. The same goes for perennials that won’t make room for other plants in the garden. And daylilies are one of the biggest offenders; quickly crowding out other, smaller species with their big, drooping foliage. But don’t despair. Just follow the simple steps below and you’ll have things back under control in a jiffy. Continue reading →