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Animal pests

What are all of the different types of ferns that voles eat? Peg, Memphis
Hi, Peg in Tennessee: There are a few different kinds of voles, but the pine vole is usually the culprit of underground damage. Prairie and meadow voles feed aboveground, so depending on what part of your ferns are being consumed will determine the type of vole you are dealing with. If you are pulling up ferns and the roots have been eaten then pine voles are likely the culprit. Voles are small mammals that create underground tunnels, burrows, and runways. These critters are only 4-5 inches long at maturity but can do some serious damage to plant material. They usually live in loose soil as this makes it easier for them to dig their tunnels. These tunnels can be a foot deep and contain many adult and young voles. These rodents do not venture very far so it would be feasible to trap them depending on the space you are dealing with. Identifying the culprit is the first step in solving the problem. Unfortunately, there are no ferns that are vole-proof. To find an active tunnel walk on top of the elevated areas and then keep an eye on them for the next day or so to see if there is any disturbance. If so, you can set a trap.

Diseases of garden plants

I have a couple of evergreens (I think some sort of yew and maybe a blue spruce) that look like they're dying but I don't know why. They were well-established on my property when I bought my home (several years ago) but I believe this has gradually happened over the last year for some reason. I have pictures if that would help. I am afraid it may be too late to save them but I want to do what I can to try. A., Fort Knox
Hello, A. in Kentucky: Some browning and inner foliage drop is normal on evergreens but if the damage is more widespread then something else is going on. Insect and disease issues are specific to plant species so it is unlikely that they are suffering from the same issues. Spruces are subject to a number of different problems but fungal issues are the most common. Damage normally begins on the lower branches and over time works its way up. Yews (Taxus) are also susceptible to fungal issues, especially in poorly drained sites. At this time you can remove the damaged foliage and take a sample to your County Cooperative Extension Service or a local garden center for a horticulturist to look at. The problem needs to be positively identified before treatment options can be discussed. For now, you will want to keep the area under the plants free of plant debris because this is a wonderful environment for insects and disease to live. Plants that are already stressed are more susceptible to insect and disease problems. These are established plants but at this point you want to avoid fertilizing, and if Mother Nature does not provide moisture you will want to make sure they get watered during the summer heat. Unfortunately, once evergreen foliage begins to turn it is usually too late to prevent further damage and in most cases they do not put on new growth to replace the lost.

I have Easy Does It roses that try to grow and bloom, but the leaves and buds grow in wads. My other rose is doing fine. Could it be the grafting? Ann, Wallingford
Hi, Ann in Kentucky: Easy Does It roses are a newer introduction that were developed for their showy flowers and for their disease resistance. I am not exactly sure what you mean by “wad” like flowers and foliage but these floribunda roses do flower in clusters. Do the roses actually bloom or do they form and drop? Do you see any unusual features on the foliage? Clearly, they do not look like the one healthy rose and so I am wondering if they are planted in the same space? Is it possible that the other two roses are not getting as much sun as the happy one? These roses are considered disease resistant but just like any other plant if they are not growing in ideal conditions, they are a lot more susceptible to insect and disease issues. Roses demand a minimum of six hours of direct sun, nutrient-rich, well-drained soil, and good air circulation. In general, there are a number of different viruses and fungus problems associated with roses and a positive identification is necessary before treatment options can be discussed. Without seeing your roses I can’t be more specific so you should take a sample of your roses to a horticulturist at a local garden center or your County Cooperative Extension Service. You can visit the Fleming County Web site at http://fleming.ca.uky.edu. For now, make sure that the area around your roses is free of fallen plant debris; this is a great environment for disease spread. If the roses are grafted and the understock is taking over it would not give your roses the characteristics that you described.

My question is two-fold: I have a willow tree with some sort of fungus on the trunk and branches. Is there a cure? Next, I have a sassafras tree growing about 55 feet from the willow. Each year it gets in full bloom but the tips of several branches are bare of any foliage. Could the same fungus be attacking both trees? Ron, Monticello
Hi, Ron in Kentucky: As a general rule insect and disease issues are specific to individual plants, so it is highly unlikely that the issue with your willow is the same as your sassafras. Depending on the species of willow (Salix) you are growing, they are susceptible to many insects and fungal problems. Scab, blight, and canker are all possibilities and all of these can potentially be devastating to your tree, so it is important to prune out all infected branches now and dispose of them. As the leaves drop in the fall be sure to rake and dispose of them so the spores can’t over-winter and cause further spread. Fungicides may be an option but it is necessary to have the fungus properly identified first. Sassafras is a native tree that does not typically have a lot of issues. Like all plants, if they are stressed and not growing in ideal conditions they are more susceptible to disease. Is it just at the tip of the branches and does it put on new growth throughout the growing season? This does not sound too alarming but it is best to have a certified arborist come out and take a look at your trees. You could also take a sample of your trees to your County Cooperative Extension Office to have the horticulture agent take a look. You can visit the Wayne County Web site at http://wayne.ca.uky.edu. They may also be able to give you recommendations for certified arborists in your area.

Evergreen plants

I have planted eight ilex glabra compacta bushes in open sun and one has appeared to have dried up. It looks like leaf burn. The leaves turned brown and fell off. What can I do to save the bush? Maria, Dobbs Ferry
Hi, Maria in New York: I am sorry to say that it does not sound good for your inkberry. If the entire plant has brown, crisp foliage it just needs to be dug up and replaced. So, the real question is why did this happen and do the rest of the plants look healthy or is their foliage starting to brown as well? If these are new plantings it may be that this one was declining even before you planted it and, depending on the guarantee policy from where you purchased them, you may be able to have it replaced. You should take the plant or at least a sample of it to the garden center/nursery to have them look at it. Inkberries are not susceptible to many insect or disease issues and are pretty adaptable to most light and soil conditions, but prefer to grow in full sun and moist, acidic soil. Insufficient moisture levels are the most likely cause so make certain that the rest of your evergreens are receiving a couple of inches of water each week. A thin layer of mulch will help retain soil moisture. Water only the soil and not the actual foliage if Mother Nature does not provide sufficient rainfall. Sometimes we just have plant decline with no explanation and hopefully it is just the one plant that will need to be replaced.

If I plant a Vanderwolf's Pyramid limber pine, can I safely keep it from getting any larger than about 6 feet wide and 15 feet tall while also maintaining the nice the pyramid form? Kerry, Smithfield
Hi, Kerry in Kentucky: Vanderwolf’s Pyramid is a cultivar of Pinus flexilis, commonly known as a limber pine. This upright evergreen will reach 20-25 feet tall and 10-15 feet wide at maturity. Unlike the species, this cultivar is a fast grower, putting on an average of 25 inches per year. They are adaptable to soil conditions but prefer moist, well-drained sites. These evergreens are not susceptible to many insect or disease problems, which makes them desirable. When choosing plant material it is best to take into consideration the mature size of the plant and plant accordingly. This will reduce stress and maintenance on your part as the plant matures. Pines are a bit tricky to prune, they have to be pruned just as the new growth is emerging. Pines put on one flush of growth per year and these new shoots are called candles. As the new growth emerges in the spring you can take off no more than one-half of each candle. This will help maintain size but if you prune too far back into the woody stems, no new growth will occur and the entire branch will eventually die. You might be better off choosing another space in the garden where this pine can reach its mature size or maybe consider a smaller evergreen altogether.

Landscaping

Do cedar chips repel hummingbirds or butterflies, and are they harmful to these critters? Jill, San Clemente
Hi, Jill in California: There are many options for mulching the garden and cedar mulch is one of the most popular. Cedar mulch does have an insect-repelling quality because of its scent. This is both good and bad depending on the insect; some are beneficial. It is not harmful to butterflies and hummingbirds but if your goal is to attract them then you might want to consider other options. Cedar mulch in general does not break down as fast as other mulches like pine straw or hardwood, so it does not add nutrients back to the soil as fast as other mulches may. Freshly chipped cedar can be harmful to plants and potentially change the pH of the soil, so you want to make sure it is fully composted for at least a year before you use it as mulch in the garden.

I have two snow ball bushes. They bloomed the second year after I planted them. I've had them for approximately five years. They have not bloomed for the past four years. Is there something I can do to get them to bloom? Virginia, Mount Vernon
Hi, Virginia in Kentucky: I assume you are referring to hydrangeas when you mention snow ball bushes. This common name is sometimes used for viburnums as well, so please let me know if I am assuming wrong. So, the first year they did not bloom in your garden was probably related to the plants concentrating their energy on root establishment instead of flower development or maybe they were planted past their bloom time. What, if anything, has changed between the second year when they bloomed and the following several years that they did not? It is still very early in this growing season and they should not be blooming at this point. Potential possibilities for bloomless hydrangeas are lack of sunlight, nutrients, or both, and pruning at the wrong time of year. Is it possible that your hydrangeas are receiving more shade than in the past? If your shrubs are growing in dense shade, they would benefit from more sunlight, preferably morning light and afternoon shade. How often are you fertilizing? Hydrangeas will benefit from a side dressing of compost or a slow-release, well-balanced fertilizer such as 10-10-10. Avoid feeding them in late summer since they are getting ready to go dormant and this will encourage growth that can be damaged by early frost. They can be fed twice during the growing season. Always follow recommended application rates since over-feeding our plants can have the reverse effect in that too much nitrogen will stop them from blooming. Some species of hydrangea, like the common macrophylla, bloom on previous year’s growth (old wood) and they should be pruned after they have finished blooming in the summer. Pruning at other times of the year will result in bloomless hydrangeas. These should not be pruned in the spring other than to remove dead wood. Hopefully one of these possibilities will make sense and you can remedy the problem.

My pachysandra is being invaded with weeds. Is there a weed killer I can use that will not kill the pachysandra? Bob, Harmony Township
Hi, Bob in New Jersey: There are both native and non-native pachysandra species. The terminalis species is native to Japan and the procumbens species is native to the United States. Both are evergreen, shade-loving groundcovers. Pachysandra terminalis can be aggressive in some areas. Both prefer to grow in moist, well-drained, acidic soil. As for weeding, the safest method is hand-pulling. Spraying any type of weed killer is not safe for your groundcover but applying a pre-emergent herbicide such as Preen or corn gluten (organic option) will be effective in terms of future weed control. These products prevent seeds from germinating but will not kill existing weeds, so your best bet is to hand pull and then apply a granular pre-emergent. Weeds are typically only a problem with new plantings of pachysandra. As the groundcover becomes established it will spread by underground rhizomes and form a dense mat. At this stage any potential weeds will not be able to compete for sunlight and/or nutrients.

Since moving to Kentucky I have really missed camellias and azaleas in my yard. What variety can I grow in Kentucky and where in Louisville can I buy them? Fran, Crestwood
Hello, Fran in Kentucky: As gardeners, it can be difficult to leave our gardens when we move but it also gives us the opportunity to create a new one. I hope you are enjoying your new home and planning your new garden. In the Louisville area we have many choices for both camellias and azaleas. Although there are exceptions, camellia sasanqua are generally more cold-hardy than camellia japonica. The flowers are not typically as large as the japonicas, but the sasanqua have been hybridized so that they are available in an array of flower color as well as size. Camellias are best planted in the spring or summer if you are going to be around to water them. Even though some are more cold-hardy than others, it is a good idea to get them in the ground earlier in the year so that the roots can establish themselves before the cold winter arrives. These acid-loving plants are happiest growing in a space where they will receive morning sun and afternoon shade. There are many different cultivars, including the April series, that are good options. These are japonicas but a bit more tolerable of the cold temperatures. The Ackerman hybrids developed by Dr. Ackerman of the U.S. National Arboretum are also good choices. Any of the winter series will all do well in your new garden. ‘Pink Icicle,’ ‘Two Marthas,’ 'Taylors Perfection,' and ‘Freedom Bell’ are other cultivars to consider. As for azaleas, there are more that can grow here than we can’t so depending on the mature size, color, and evergreen preferences you will have a wide range to choose from. If you have not discovered Yew Dell Gardens in Crestwood it is absolutely worth the visit. They have wonderful plantings of both azaleas and camellias. Boone Gardiner on Old LaGrange Road is probably the closest to you but The Plant Kingdom on Westport Road and Wallitsch Nursery on Hikes Lane are all reputable sources for quality plants.

When is the best time to transplant a hibiscus? Melinda, Wayland
Hi, Melinda in Kentucky: Perennial hibiscus are show-stoppers with their large blooms. They can add a tropical feel to any sun-loving perennial garden. They can be a bit tricky to transplant but if done properly you can be successful. The best time to transplant your hibiscus is during the spring just as new growth starts or later in the winter. These plants are one of the last to break dormancy in the garden so you will have plenty of time to move them in this spring. When it is time to move them, have the new holes prepared before digging up the hibiscus. Be aware that these perennials have an extensive root system, and keeping as much of the root ball intact is essential for a successful transplant. The idea is to reduce the amount of transplant stress. Once you have gotten them out of the ground, place them on a tarp or a large piece of burlap to gently move them. Make sure the new holes as just as deep and twice as wide as the root ball. Plant them and treat them like you would any new addition to the garden. Additional moisture will be needed if it is a dry spring/summer. A thin layer of mulch will help retain moisture. Make sure to choose a space where the hibiscus will receive full to part sun. It may spend a lot of its energy getting its roots established so don’t be too concerned if it does not bloom like it has in previous years.

Vegetables

When are the signs right to put out my tomato and other vegetable plants? Karen, Gamaliel
Hi, Karen in Kentucky: Tomatoes are considered warm-season crops and are safe for planting now. In the Louisville area our average frost-free date is May 10; you are farther south and so you can plant a bit earlier than we can. Cool-season vegetables like broccoli, cauliflower, green onions, kale, and other greens can be planted in the early spring and again as the temperatures cool down in the fall. Warm-season crops like tomatoes, peppers, eggplant, beans, and the majority of other vegetables require warm air and soil to grow properly. Vegetable crops may have their growing season but they all prefer the same growing conditions. A vegetable garden should be south-facing so it will receive optimal sunlight. The soil should be nutrient-rich and most vegetables prefer the soil pH to be between 6.2 and 6.8. If you have not added compost or other amendments to your soil recently your plants will benefit from doing so. If you want more detailed information on growing vegetables in Kentucky, the following publication is available to home gardeners from the Extension Service. Visit www.ca.uky.edu/agc/pubs/id/id128/id128.pdf to read this publication.
Angie McManus Our Garden Expert Angie McManus will answer your questions.