Garden Questions of the Week

My roses are developing spots and holes in the leaves. Any idea what this is? I don’t see any bugs.” -Right now, we’re getting samples and questions about rose leaves having either window panes type holes or complete holes in the leaves, but no bugs to be seen. Well, chances are that’s the results of the rose slug. Rose slugs are actually in the sawfly family, and there have been different types seen, ranging from 1 to multiple generations each year. They look like very small caterpillars (at the early stages are very hard to see), and typically feed on the underside of the leaves, causing the window pane effect from the younger slugs, to skeletonization as well as the large holes as the larva mature. Control for the rose slugs includes 1.) Hand picking the infected leaves (with saw fly larvae on them) and destroying the leaves, 2. Repeated foliar sprays as needed, using Insecticidal Soaps or Horticultural Oils, and be sure to spray the undersides of the leaves, or 3.) By applying a systemic such as Bayer’s or Bonide’s 3 in 1 Rose Care. The foliar sprays are usually the most effective immediate control, but a combo of the above works quite nicely! (By the way, being they are saw flies, Bt is not an effective means of control.) Of course, these methods of control also work quite nicely with the aphids as well.

“I have a layer of thatch in my lawn. Should I rent a thatch machine and thatch it?” -Now’s not a good time to be doing that, as you’ll be dealing with weed seeds for the rest of the summer. And, we really have gotten away from those dethatchers, and are now core aerating on a more regular basis. Core aerating opens up the thatch, and actually promotes a quicker breakdown of the layer, without dealing with tearing up the turf and exposing all those weed seeds. Still time to core aerate now if needed.

“When can I divide my daylilies?” -Tough cookies those daylilies! They can be divided in the spring, in the fall, or after they’re finished flowering. By the way, if you want to keep those rebloomers reblooming this summer, be sure to deadhead spent flowers and eventually the entire flower stalk, and feed after each flush of flowers.

“Can wild bush honeysuckle be transplanted?” -Can it? Sure. BUT DON’T! That wild bush honeysuckle has become one of the top 10 most invasive non-native plants in the state of Ohio, as well as all through the N.E. United States. We want to get rid of it, not propagate it. It is not wanted, and we need to become more aware of its invasiveness and ways to get rid of it. Physical removal of the smaller plant and roots, removal of the root crown for medium to larger honeysuckle (use a ‘Honeysuckle Popper’), or for the really large ones, cutting them off at the ground and immediately painting the stump with concentrated Roundup works. DO NOT LET WILD BUSH HONEYSUCKLE EXIST ON YOUR PROPERTY.

“Is it true that when my late blooming Spirea finish flowering, I can prune them and they’ll flower again?” -Yes, surprisingly enough. Simply take the hedge shears (one time that hedge shears can be used!) and shear off just below the spent flowers. Reshapes the spirea, and the new growth typically flowers again.

“My peach tree has developed wrinkly contorted puckered leaves that are turning yellow and red in those areas. What is that and what can I do?” That is peach leaf curl, and at this stage, nothing you can do. It will cause defoliation of those leaves and some fruit drop, but doesn’t kill the tree (collect and pitch fallen leaves and fruit). Use normal care tactics to keep the tree healthy. Spray with a fungicide in the fall (after most leaves have dropped) and or in the spring just as the buds begin to swell.

“I have an area that only gets sun about 4 hours of the day. Anything edibles I can grow there?” -If you can find a spot with 6 hours plus, you’re good with many of the edibles. But for less than 5, maybe some dappled shade, look at the greens like lettuce, chard, spinach, arugula, etc, many of the herbs, maybe even radishes. If you have only a couple sunny spots, don’t forget container gardening for those veggies that need full sun.

“I have patched of clover in my yard. How do I get rid of it?” – At one time clover seed was added to grass seed mixes especially in newer lawns. Clover takes nitrogen out of the air and makes it available in the soil, feeding the lawn for free! Clover is usually greener than the lawn, earthworms love the soil when clover is present, its disease and drought tolerant, and avoided by most turf pests. The flowers are an important source of nectar for honeybees and can be picked and tossed in with your salads. So why get rid of it? Flowering plants in the lawns are just not accepted anymore. Like with most ‘weeds’, when clover shows up, it’s usually telling you that the lawn has thinned out, and allowed the clover room to grow. Make corrections for the lawn to re-grow thicker (keep the lawn healthier – feed regularly (keep nutrient levels up) – mow at a higher level – core aerate – raise sunken spots and improve drainage, etc). A thicker lawn means less clover (as well as the other weeds). – To get rid of clover patches ‘naturally’, hand pull out of the grass in smaller yards. Apply corn gluten meal on a ‘multi-year program’ to stop clover seeds (pre emergent herbicide), as well as adding nitrogen to your soil (multi-year program as the seeds can lie dormant for several years). Combine these with good lawn care practices and you should be able to take care of the clover, over a couple years, ‘naturally’. – If you need to get rid of it now, spray the areas with a weed killer that will kill clover but not the lawn. Make sure that it clover listed on the label for weeds controlled. It’s a tough perennial weed and not all weed killers will do it. Add ‘Spreader Sticker’ for a better kill. Do not spray the entire lawn – simply spot treat the clover patches. And the best time to spray for clover control? Mid to late spring works, and may take multiple spot treatments, but the absolute best time for clover control is in the fall!

Garden Questions of the Week

“What is your philosophy on lawn insect control, specifically controlling grubs? Do you wait until you have a grub problem, or head them off at the pass? Anything all natural for grub control?” -Remember a thick healthy lawn can withstand 10, 12, 15 or so grubs per square foot without showing much if any turf damages. So a healthy lawn is your best defense. If you have had problems, or want to prevent problems, use a grub preventer in June. Rarely are other insects a major issue, especially with tall fescues, so rarely are general insecticides used on the lawn (type of grass will make that vary a bit). Nematodes are getting some attention for grub control but haven’t used them or seen a lot of research done using them in our area. Milky Spore has been around for a long time (bacteria) but only goes after Japanese beetle grubs, needs grubs to infect to be able to spread and survive in the soil, and have also been informed it’s not as potent as it once was. So not high on my list for recommendations – although some folks use it and say it does a good job – others have said just the opposite. If you do wait until the grub damages are visible, you can treat with a grub killer at that time (different than a grub preventer), and then re-seed or re-sod the damaged areas.

“Can we use grass clippings as mulch in the garden if the lawn has been treated with a weed control?” -NO! Throw those clippings back into the turf for the season and let the lawn enjoy them.

“Why are my maples leaves falling now?” -Chances are its either maple petiole borer or maple leaf anthracnose. Neither of which are sprayed for, won’t kill the tree, and should stop in little while.

“Why are my ash leaves dropping?” -Chances are its either Emerald Ash Borer, or if brown on the tips, curling, etc, it’s probably ash leaf anthracnose. Again, for the anthracnose, it’s rarely sprayed for, won’t kill the tree, will stop in a week or 2. Emerald Ash Borer – well, that’s another story.

“Why are my sycamore leaves distorted and dropping?” -Want to guess? That’s it; sycamore anthracnose. See above question and answer!

“Why do my maple leaves have little warts all over them?” -That’s a gall, and there are several types which caused by a small mite stinging the leaf buds. The leaf forms a nice little house around the insect’s eggs, they hatch out, goes away, the gall dries, falls off, and leaves a small hole in the leaf. Again, leaf galls will not kill the tree, rarely to never sprayed for, and is pretty much aesthetic. (That means it looks funny!) Oaks get them, as well as many other types of trees. Again, if you’re not sure, you can always take a leaf sample to one of our garden stores and someone can identify the problem.

“When my mums are growing, aren’t I supposed to be doing something to them like cutting them back?” -Why, yes, yes you are! Pinching your mums between the time they’re 6-8 inches tall, until around July 15th or so (usually 2-3 pinches is all that’s needed), you’ll keep those garden mums more compact, fuller, and have a lot more flowers in the fall. As a matter of fact, some early blooming varieties will start flowering soon if they’re not pinched back to delay the flowering process!

“What’s the green stuff growing on my tree trunk?” -It’s called lichens, and is an unusual combination of algae and fungus growing together on the surface of the bark. No harm – leave it alone.

“I’m ready to plant my annuals but the foliage is there from my spring bulbs. Can I cut it off now?” Getting close or may be there! We recommend leaving the foliage on spring bulbs for at least 6 weeks after they finish flowering, or they start to yellow and brown – whichever comes first. Then remove the foliage. You can dig and move them at that as well.

“Is it safe to spray a weed killer in the landscape beds to kill the weeds? Won’t it kill my landscape plants?” -Use a non selective herbicide such as Roundup / Kleenup or Killzall, and only spray it on the weed. These products only spread thru the plant and roots, but not thru the soil. Keep the spray on the weeds, and your landscape plants are safe. Remember, also using a pre emergent herbicide like Preen will help stop weed seeds from growing in your landscape beds. Preen for the seeds, Roundup for the weeds. (And lawn weed killers are for the lawn, not landscape beds.)

“I need to prune my lilacs. When should I do that?” -Prune lilacs within 3-4 weeks after they finish flowering. The later you wait the fewer lilac flowers you’ll see next year.

“Have the bagworms started to hatch yet?” -Yes they have so keep your eyes open for them! Keep watching your evergreens especially. Once you see them active on the plant, spray with Bt or Bonide’s Captain Jacks Deadbug Brew.

“Why are the leaves on my crabapples two different sizes this time of the year?” -Well, the smaller leaves were the first set of leaves sent out by the tree, at the same time the tree was flowering and setting fruit – which takes a lot of energy from the plant, so smaller leaves. The next shot of growth gets more of the plants energy, so larger leaves.

“Why do you send out your newsletter with black lettering on a green background. It is not readable at all. Would you please change it or provide an option for the readers to do so. I miss reading your wonderful newsletters.” -Thank you for the input! We’ll take a look at that next time we redo the format. But in the meantime, simply go to the bottom of the page, and click on ‘Printer Friendly’. That changes it to a white background and should make it easier for you to read (won’t print out unless you tell it to).

Garden Questions of the Week

“We have been growing the Bjut jolokia (ghost pepper) for 3 years now. Is it still the hottest pepper in the world?” – I’m sure it is for many folks, but believe it or not, there have been 3 new hottest peppers take over the title! The heat in peppers is measured in Scoville units – jalapeños usually come in around 2,500 scoville units and habaneras around 250,000 to 500,000 units. But these peppers are in a totally different category with Bjut jolokia coming in around 1,000,000 scoville units! Last year, ‘Naga Viper’ took the title with 1,359,000, only to be dethroned by ‘Trinidad Scorpian Butch T’ at 1,463,000, only to be dethroned by the current world’s hottest pepper ‘Trinidad Monuga Scorpian’, coming in at a scorching 2,009,231 Scoville units! And yes, Natorp’s grew a very limited amount of all 4 pepper plants being sold at the garden stores.

“We placed newspaper in between the rows in our garden as a weed barrier. Can we use grass clippings from a ‘treated for weeds’ lawn as the mulch on top?” -NO! Definitely not! Grass clippings are excellent soil amendments and mulch for the garden, but not if the lawn has been treated with herbicides. Return those clippings back into the turf.

“We’re growing the horseradish in 18 inch pots. When do we harvest them? This is the second year and they’re flowering.” Harvest container horseradish in the fall of the second year. Slide the plant out of the pot, and you should have a solid mass of smaller nice white horseradish roots. Funny how the flowers actually smell like horseradish! (Ps – Smaller / newer leaves can be picked and used in salads.)

“We want to do more container gardening, but the watering has us thinking twice. Any suggestions?” -If you have many containers in the same area, consider installing a micro irrigation system (drip) that would water all the pots for you by simply turning on the water. Not that expensive and well worth the investment. But there are a couple others you may try. First, make sure you use a top grade potting mix. The main ingredient will be sphagnum peat – very airy yet holds moisture, which is very important in container gardening. After you have the top grade potting mix, there are 2 products that can be added to help maintain moisture even longer. Coconut coir – looks and feels like sphagnum peat, this by product of ground up coconut hulls is also extremely airy, and actually holds more moisture than sphagnum peat! And Soil Moist – these small polymers, when mixed with your potting mix, soften, swell, and absorb and hold water, until the soil dries out, then releases the water back into the soil to help water the plants. Somewhat like a water reservoir. The expanding and contraction also helps in soil aeration. When using Soil Moist, be sure to follow the directions, and incorporate it into the root level of the potting mix, not at the top or surface. Two more products for container gardeners – always have a good watering wand to water with, and I love the Dramm series of watering wands. And if you need to go out of town for a couple days, try using Aquacones. Attach a 2 liter bottle of water, punch out the drip hole, place in the soil, and these will slow drip water your container. Soak the soil really well just before you leave, add the Aqua cones, and you should be good to go for at least a couple days.

“My roses are developing holes in the leaves, but I can’t find anything eating on them? Is this a disease, or what am I missing?” -Not a disease, it is an insect, and a hard one to see and find. It’s called a rose slug, and is not a slug at all. It’s a sawfly, and looks like a small lime green caterpillar (looks like the veins on the bottom on the leaves). Rose slugs feed on the undersides on the leaves, so what you notice are small white dots, then small holes, then larger holes that look like windows. And if they get really bad, they eat almost all of the leaf. Control for the rose slug includes hand smashing when you find them, applying a systemic insecticide around the base of the rose, and repeated foliar sprays of insecticidal soap or horticultural oil, spraying the undersides of the leaves.

“When you’re growing your tomatoes in containers, what size pot do you use, and what fertilizer do you recommend?” For tomatoes, the larger the pot the better! This is one time bigger is really better. I like 20-25 gallon pots, but anything 18 inches or larger will work. I add Osmocote for a slow release fertilizer and a source of calcium to the potting soil. And yes, add Soil Moist (now also using coconut coir) to help reduce watering, which the larger pot will help as well. For the fertilizer, I use Espoma’s Tomato Tone (has calcium added). And plant your tomato plants deep, for better rooting.

“Any tomato better to grow in pots than others?” -Not really. I think all of them can be grown in pots, but unless you have a means of supporting them, you may want to try the determinate rather than indeterminate tomatoes. ‘Husker Red’ and ‘Husker Red Cherry’ are two examples of determinate tomatoes. Stocky, usually only require a support stake, but can be caged for extra support, and only grow 4-5’ tall – more of a bush form. Indeterminate tomatoes can be grown in pots – they just need caging / supports for 5-9’ vines. Also look at the newer selections of cherry tomatoes grow just for hanging baskets and smaller pots like ‘Tumbling Toms’ (red and yellow). So many choices of tomatoes today you can go nuts trying to decide which ones to grow! But that’s a fun thing.