My white pines are maturing and smothering the lawn with pine needles underneath. They were originally planted by the former owner as a privacy/sound barrier. They are beautiful but take up an ever-increasing amount of landscaping and gardening space. If I only cut off the lowest line of branches, what shrubs will adapt to all the falling pine needles and shade to keep our vision and sound of the road behind us to a minimum? Anything that flowers or has good fall color would be a bonus. J.S., Novi

White pines shed needles just like deciduous trees shed leaves. And as the pine tree grows, the once dominant lawn begins to shrink and decline. Lawn turf needs sun and water to thrive, neither of which it will get under an ever-expanding pine. So don’t try to resuscitate any lawn under the canopy. If the trees have not become misshapen as they’ve grown together, it might be feasible to remove one or two to allow the others to complete the job of filling in. There is a plus to those pine needles. They make great winter protection not only for the pine tree, but also for other perennials and plants in your landscape. Use some of the abundance as mulch and acidifying compost around plants in other garden beds.

Understand that the best noise barrier and privacy fence you have is leaving the pines alone. Perhaps a focal point bed placed several feet in front of the pines and bermed a couple feet above the plane of the lawn may offer you that colorful relief. The pines would serve as a great green backdrop to a mix of seasonal flowering shrubs and perennials that you could enjoy all year without jeopardizing your natural screen.

If you still want to remove the lower line of branches, remember you are dealing with very dry shade and low light. Anything you plant must be out past the drip line of the pine tree by several feet in order to maximize its sun and water exposure. Be aware that even removing the bottom row of branches will not prevent the expansion of the pine tree canopy and width. Whatever you plant may have to be moved as the pine trees continue to grow. To maintain minimum road noise and privacy year-round, you might try a contrasting low-growing evergreen. One such drought-tolerant shrub is the juniper ‘Gold Star’ with yellow needles. You can intermix perennials such as variegated-leaved hostas to lend brightness to the shade. There are a number of perennials available today that would suit your conditions. However, most do not have four-season presence and will not replace the screening of the pine tree branches.

I planted a small tree in early June and animals began chewing on the bark in late June. I know that tree wrap is normally used in the winter, but is it safe to use it in the summer? I don’t want to cause disease problems on the bark.

Rather than using paper tree wrap, try the plastic coiled wrap that is flexible and perforated to allow air circulation. It comes in assorted diameters as well, so you can custom fit it to the current caliper of your tree and allow room for growth. Reputable nursery and garden supply centers carry this product. Nursery stock trees will often already have this flexible coil around the trunk. You only need it about two feet up from the base, which is about the height a rabbit can stretch.

Young deer will sometimes sample bark to see if it’s tasty. But they really prefer new leaf and flower buds. If you have evidence of deer, such as droppings or hoof prints, you may have to resort to spray products such as Deer Off. It is a citrus and peppermint-based spray, which lasts about two to three months. It does not wash off in rain or irrigation cycles. It clings without deforming or adulterating the plant by using vegetable oil as its agent. Deer have much better noses than we do, and they find the peppermint scent and taste unpalatable.

Meadow mice (voles) and rabbits, however, are generally the culprits for chewed bark. Occasionally juvenile groundhogs will also sample young tree bark. (A bit like human babies putting everything in their mouth to get the taste and texture.) Young trees are more succulent and desirable as creatures forage for food for themselves and their broods.

If there are raised tunnels in the vicinity of your tree, then more likely you are dealing with voles. Place three or four simple plastic snap mousetraps baited with a dab of peanut butter around the base of the tree. Check the traps each morning for a week. If the traps are sprung, remove any remains and re-bait them. If done consistently, you may eliminate the entire offending colony within that period. The perforated plastic tree wrap will also deter the rabbits and frustrate the groundhogs. Using both methods should protect your tree from additional damage.

I have a couple large patches of mushrooms coming up in my lawn and in bark mulch I put down last fall. Should I dig them out? Should I do anything else to make sure that they do not grow back? Or should I just leave them alone to die on their own?

The sudden appearance of mushrooms in our lawns always sets our blood racing. What caused these “alien life forms” to appear overnight? In reality, mushrooms are just the fruits of a fungus caused by rotting wood in the soil that may have come from past construction or old tree roots and stumps.

Since you are seeing them in bark mulch you applied, the fungus spores were probably in the mulch and while still dormant, hitched a ride into your yard. This doesn’t condemn your mulch source nor do you need to remove the existing mulch and put down fresh. Mushrooms do not harm the grass or the mulch.

They should, however, be hand-picked or raked out to prevent the fruiting bodies from producing more spores and increasing their numbers. If you mow over them, you may carry spores to other parts of your lawn on your mower blades. There is no chemical that will prevent them.

Since a fungus prefers moist, shady conditions, you may want to check how often you water your lawn and the amount of air circulating in that area. Removing the mushrooms present and monitoring your maintenance methods should decrease their colonization.

My lawn started to turn brown in early July. Can I get it back to green before it goes totally brown? One of my friends heard that once it is dormant, it will not come back until the fall.

July begins true summer in Michigan. We have had few soaking rains to benefit gardens and lawns. So, lawns that are not watered consistently will go brown and dormant to survive the lack of moisture.

Your friend is partially correct, assuming you are relying solely on Mother Nature to water your lawn. If your grass is healthy when summer approaches, it will naturally go dormant and turn brown. When temperatures cool down in fall and there is more rain as the seasons change, the grass naturally perks up green again.

You don’t need to panic that your brown lawn means it will die. It simply means the activity above ground shuts down until more water becomes available. The grass has food stored in its roots and will recover easily as soon as water becomes available.

Therefore, if you want the lawn to reactivate, you need to devise a consistent watering schedule and more closely monitor natural rainfall. Next, be careful not to mow your lawn too short during summer months. Leaving the lawn at 2 to 3 inches provides shade to the turf roots. Taller grass also helps prevent evaporation and makes recovery easier.

You can prevent a lawn from going dormant during a dry, hot summer by keeping it evenly watered. How much water depends on the type of soil. Clay soils hold water better than sandy soils, which drain quickly. Set out your favorite sprinkler and place a large-mouth jar or container in the spray pattern. Watch to see when you’ve collected about two inches of water and note how much time it took. Two inches of water is enough to penetrate any type of soil 6 to 8 inches deep. By augmenting natural rainfall, you can return your lawn to green status and avoid the summer dormancy period.

Each year my impatiens grow very tall (over 2 feet) and are healthy, but they are not covered with flowers like those I see at other homes and even commercial plantings. How can I get my impatiens to grow lower and give me that “carpet of color” effect?

Impatiens are a good selection for shady spots for a number of reasons—the plants thrive in both beds and containers, plus they come in a wide range of flower colors including red, orange, salmon, rose, pink, white, violet, and lavender blue. New Guinea impatiens also offer exciting variations in leaf color.

With proper care, impatiens will fill your flower beds with color until frost. To ensure impatiens flourish, you need to do several things. First, plant impatiens in the right soil. The plants prefer well-drained soils with a pH of 6.0 to 6.5. After preparing the soil, you are ready to plant.

Choose healthy transplants, free of disease and pests, from a local nursery or garden center. The common impatiens actually prefer shade. The New Guinea impatiens with variegated foliage will tolerate morning sun. Take this into consideration when you select plants. Space tall-growing varieties 18 inches apart and compact varieties 8 to 10 inches apart. The closer they are planted, the taller and leggier the plants grow.

Once plants are in their containers or beds, provide them with ample water. Impatiens need plenty of water during the hottest parts of the summer. Check plants regularly. You may need to water daily during hot weather. Plants under stress from insufficient water will not bloom as heavily as healthy plants. Use soaker or drip hoses in flower beds. These hoses put the water where it’s needed (the roots) and are more economical than overhead sprinkling.

Impatiens respond well to fertilizing. Applying a water soluble fertilizer once a week encourages foliage and flower development.

When the summer really begins to bake the garden, impatiens may look spindly and leggy with only tufts of foliage at the top of long stems. There’s an easy solution to that problem: Pinch or cut back stems to within three inches of the plant’s base. Impatiens have suppressed leaf buds along their stems. When you remove the upper growth, the plant responds by opening the suppressed buds. This pruning will encourage a new flush of growth and blooming for you to enjoy the rest of the season.

I read that you should never plant the sweetgum tree (Liquidambar styraciflua) between the sidewalk and the street because of the spreading roots, but is this true for all varieties, such as ‘Moraine,’ ‘Burgundy,’ and ‘Rotundiloba?’ Which variety is more cold hardy in Michigan? I read that ‘Rotundiloba’ has no spiky gumball fruit, but is it hardy to zone 5? Finally, which variety can be counted on for reliable fall color?

Sweetgum (Liquidambar styraciflua) grows in a narrow pyramid to a height of 75 feet and may spread to 50 feet. The beautifully glossy, star-shaped leaves turn bright red, purple, yellow or orange in the fall. On some trees, particularly in the northern part of its range, branches are covered with characteristic corky projections. The trunk is normally straight and does not divide into double or multiple leaders. Side branches are small in diameter on young trees, creating a pyramidal form. The bark becomes deeply ridged at about 25 years old. Sweetgum makes a nice conical shade tree for large properties when it is young, developing a more oval or rounded canopy as it grows older as several branches become dominant and grow in diameter.

Be careful when locating sweetgum as a street tree since its large, aggressive roots may lift curbs and sidewalks. Plant trees 8 to 10 feet or more from curbs. (Much of the root system is shallow.) The 1-inch round fruit may be a litter nuisance in the fall; people could slip and fall on the fruit on hard surfaces, such as roads, patios, and sidewalks.

The tree should be planted in soil with a pH of 7 or less. Chlorosis is often seen in alkaline soils. The seeds provide food for wildlife and will often readily germinate in shrub and groundcover beds, requiring their removal to maintain a neat landscape appearance. Although it grows at a moderate pace, sweetgum is rarely attacked by pests, and tolerates wet soils. Trees grow well in deep soil, and poorly in shallow, droughty soil. It is native to bottomlands and moist soils and tolerates only some (if any) drought. Existing trees often die back near the top of the crown, apparently due to extreme sensitivity to construction injury to the root system, or drought injury. The tree leafs out early in the spring and is sometimes damaged by frost.

The cultivar ‘Rotundiloba’ is fruitless. The leaves have rounded tips on this variety, and turn deep purple in the fall. It is hardy to zone 5b. The leaves of ‘Burgundy’ turn bright red-purple in the fall, and this variety is hardy to zone 6. In the fall, leaves are held on the tree longer than the species. The cultivar ‘Moraine’ is the most cold hardy cultivar known today. The star-shaped leaves turn bright red, purple, yellow or orange in the fall, and it is hardy to zone 5. It is the “smallest” of the cultivars with a mature height of 60 feet and a spread to 40 feet.

Is everyone having a bad clematis season? Why won’t the flowers get the normal size?

Clematis vines need lots and lots of water. That being said, they also need excellent drainage. This summer, Michigan had some periods of very hot scorching temperatures. Clematis need extra water during these hot times. If you have sandy soil, mulching and/or amending the soil is a must or it is difficult to provide enough water to the plant roots. (Remember to keep mulch from touching the base of the plants.) If clematis vines have to compete with deep-rooted trees or other plants, they may not receive enough water. If vines are starved for water, flowering and flower size can be reduced.

Shading the base of clematis is also necessary. Use plants like groundcover or hostas that do not have deep roots. Clematis vines also like to grow behind shallow-rooted shrubs or even come up through and over the shrubs. While the base should be shaded, most of the plant should climb into the sun. In fact, most vines need 6 to 8 hours of sun per day. Did a nearby tree grow larger through the years? Have you added any hardscapes like a pergola or trellis that is now shading the plant?

Also, lighter colors (generally) can take more direct sunlight than darker deep purples and reds, since dark colors absorb the light. The dark colors can suffer in bright sun and 90-degree heat, affecting flower production and size.

Clematis vines are heavy feeders, especially in spring and during flowering. Fertilizers with low nitrogen and high phosphorus are best for flowering. Watch to make sure that nitrogen fertilizers broadcast on the lawn aren’t getting near the vines. High nitrogen fertilizer will make nice leaves, but smaller or less flowers.

Some clematis need pruning and others don’t. Pruning at the wrong time or too severely can affect the blooms. In spring, wait until you see the first new shoots. If they come out of the ground, the plant blooms on new wood and should be pruned to about 12 to 18 inches from the ground in April. If the growth comes out of the nodules on last season’s vines, it is said to bloom on old wood. This type doesn’t have to be pruned. However, if they are getting weak at the top, or flower production is suffering, you can cut the vine back by a quarter to a third of its height. You may lose some bloom this year, but it will strengthen the vine overall.

Lastly, when is the last time you had your soil tested? Even if you have had it tested before, soil tends to revert to its natural state. If you have added amendments, it is good idea to check every few years to see what is happening in the soil. Maybe some critical nutrients are lacking that a soil test will point out. It will also tell you the soil pH (clematis like it slightly alkaline), and even recommend fertilizer percentages to add.

Late this summer and into early fall, I noticed a light white coating on the grass blades in my lawn. It is not all over the lawn, just in certain spots. It looks like a light coating of white spray paint. What is this, and should I be doing anything about it this fall?

Your symptoms bear the trademark of powdery mildew, a common problem on bluegrass lawns in shady areas. The mildew fungus (Erysiphe graminis) attacks the surface of the grass leaves, developing a fine, fungal growth that resembles a white powdery substance on the leaves. In dense shade, powdery mildew causes the affected areas of leaves to turn yellow, eventually resulting in the yellowing and dying of lower leaves. Even when on non-turf plants, it can often lead to plant death.

Powdery mildew develops in areas of dense shrubbery or trees where there is poor air circulation, considerable shade, and high humidity. It thrives in temperatures of 60 to 72 degrees. In many cases, selective pruning of shrubs and trees to allow better air circulation and greater penetration of sunlight can control powdery mildew. Our weather conditions this season have provided ample opportunity for mildew to occur.

Since the mildew isn’t all over your yard, take a look at the places where it is occurring. Is there limited air circulation? Are there pockets of dampness and poor drainage? If you have an irrigation system, has the timing been adjusted for natural rainfall? How often is the lawn being fertilized? Often cultural practices can be modified and corrected to minimize optimum growing conditions for mildew. If powdery mildew continues to be a problem, consider planting or overseeding with a less-susceptible grass variety or plant alternative groundcovers in those areas. Turf is not always the best green surface in areas with constant humidity and little air circulation.

Why does my holly not produce berries?

Hollies (Ilex) require both male and female plants for berry production. Berries are only produced on female plants. One male may pollinate several female plants. Only large leaf hollies (‘Blue Princess,’ ‘China Girl,’ etc.) are planted for berry production. Small leaf hollies (‘Green Luster,’ ‘Hetzii,’ ‘Northern Beauty’) are used for foliage effect and not for the black berries they produce. In order for berry production to occur, the correct pairs of male and female plants must be planted together. ‘China Boy’ will pollinate only ‘China Girl.’ Any of the male blue hollies (‘Blue Prince,’ ‘Blue Stallion,’ ‘Blue Boy’) will pollinate any of the female blue hollies (‘Blue Princess,’ ‘Blue Maid,’ ‘Blue Girl’). ‘Golden Girl’ is pollinated by any of the male blue hollies.