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“Dear Ruth” Column

Category: 'Dear Ruth' Column, Presenting "The Curious Gardener"

The Curious Gardener Newsletter

The “Dear Ruth” Column for Gardening Questions

Ruth Rogers Clausen is a horticulturist, journalist and author who is partnering with Womanswork to produce the “Dear Ruth” column.

Ruth grew up in Wales and studied horticulture at Studley College in England. She has contributed greatly to her profession as a writer of tomes (Perennials for American Gardens, Random House; Essential Perennials, Timber Press); an editor of gardening magazines; and a lecturer, advisor and judge for botanical gardens and flower shows all across the country and around the world.

For many years Ruth gardened in Westchester County, NY (Zone 6), and more recently has been gardening in Maryland where she grows an eclectic range of plants. Her plant choices reflect those plants that do well in her region and throughout the northeast and mid-atlantic.

Ruth wrote a book for Timber Press titled 50 Beautiful Deer-Resistant Plants: The Prettiest Annuals, Perennials, Bulbs, and Shrubs that Deer Don’t Eat, and more recently co-wrote with Tom Christopher a book, Essential Perennials, also for Timber Press.

Write your questions in the Comments section below and Ruth will respond in a timely manner.


206 thoughts on ““Dear Ruth” Column

  1. ruth rogers clausen says:

    Dear M.W.Gillis,
    Personally I don’t care for using any dyed mulch products, especially as I am not a chemist and don’t know what the dye ingredients are. Also I have noticed that unless finely ground they take a very long time to break down in the soil. Of course you want to suppress weeds, maintain soil temperature and moisture content, and a gc should add organic matter to improve soil texture and water-holding ability over time. Over and above this, we expect it to look pleasing as well—quite a tall order. Personally I like to use shredded leaves that break down and improve the soil. If you can get them inexpensively or without cost, so much the better. I collect bags from my neighbors and put them through a shredder, which takes work but does a good job and the leaves cost me nothing. Avoid using any grass clippings or plant material that is diseased or has been treated with herbicides. Hope this helps.

  2. Mary Lou glazer says:

    Love your site. I have a tabletop garden in my backyard and live on Long Island.
    Could you suggest fall and winter vegetables to plant now? Thanks

  3. ruth rogers clausen says:

    Hi Mary Lou,
    How nice to have a space for a fall/winter veggie garden. It’s really late in the season, but on LI try to find transplants off cabbage, kale, spinach, arugala (rocket), lettuce. Try starting radishes from seed too and hope for a late frost. In the winter I grow cress seeds on old washcloths on shallow bowls, as well as start seeds of peas, mung beans, alfalfa, and radishes to eat as sprouted seeds-good on sandwiches! Of course you can use a tray spouter for this as well if you have one.


    My lilac bushes are not doing well. The older branches seem to have a fungus (greenish scales turning bright green after a rain) and other branches without the fungus have a white powder on their leaves. How should they be treated, if at all?

  5. ruth rogers clausen says:

    Hi Rosemarie,
    You must have missed my reply to your query from last month. Never mind, here is my reply:
    Hi Rosemarie,
    It sounds like your lilacs have a case of powdery mildew. This is very common on lilacs especially after a hot and humid summer. You can spray if you want, although the leaves are gong to drop soon anyway. Be sure to rake up and destroy all fallen leaves as the spore of powdery mildew will overwinter on them.Prune out any badly infected shoots next spring as soon as you see them. Keep free of weeds and apply mulch next spring to retain soil moisture and reduce stress.You may need to thin the branches again.After 40 years consider replacing them if they are unsightly next year. They have done well for you.

  6. Alicia Williams says:

    I planted a Camillia about 4 years ago in the backyard and it has never bloomed, it doesn’t even bud. Do you have any idea why? I live in Medford Oregon, zone 7 to 8. I garden organically. I really want to see beautiful camillia blooms! Thanks for your help.

  7. Sandra Smith says:

    Hi Ruth,

    When should I cut down my butterfly bush? or can I just leave it for winter interest and cut down in the Spring or can I just leave it alone? Appreciate your help…..Sandi

  8. ruth rogers clausen says:

    Hi Alicia,
    I am sorry about your camellia not blooming. I’m surprised that it has never bloomed. I suggest you dig it up and see if the roots are nice and healthy. Perhaps it was planted, left in a metal basket container or there is something from letting the roots grow out. Was the rootball tease out gently to separate the roots at planting time? Were older roots encircling the root ball? All these things could possibly explain why your camellia is not doing well.You might need to replace it.

  9. ruth rogers clausen says:

    Hi Sandi,
    You don’t say where you live, but I advise leaving the pruning of butterfly bushes until spring.You can certainly leave it for winter interest—perhaps remove any branches that could get broken by wind to the ground now. In spring wait until you see at least 1/2″ of young growth starting before you prune, so that you know that the sap has risen. Pruning too early before a possible late frost, may require a second pruning operation later. If you don’t prune at all, the plant will just get bigger and bigger each year.

  10. Sandra Smith says:

    Sorry Ruth – I live in Wisconsin. Not sure I understand your answer because can’t all the branches get broken by the wind?? It is currently about 4 feet high. When is the best time to prune? spring or fall? Can I leave my roses also for winter interest? They are facing west behind my brick house and are still blooming this late in Oct!!

  11. Helen Huriaux says:

    I live in Baltimore city and have a partially shaded patio with two climbing white hydrangeas on a trellis against a wall. We planted them about eight years ago and after growing about 10 feet and producing beautiful blooms for about two years, they haven’t bloomed since. On the other side of our small patio fence is a large landscaped yard which provides shade. What might be the problem?

  12. ruth rogers clausen says:

    Hello Helen,
    Unless the shade is considerably deeper now than when your climbing hydrangeas were doing well (maybe your neighbor planted something large that cut the light), I doubt it is a shade problem. Perhaps the adjoining yard is fertilized heavily, especially if there is a lot of lawn, or a vegetable garden. Hydrangeas are greedy for water, but will produce lots of succulent but vegetative growth at the expense of flowers if fed too much. I wonder if the plants being overfed.

  13. ruth rogers clausen says:

    Hi Sandy,
    I am sorry that I did’t make myself clear about pruning your buddleia. Wait until spring, but then prune hard, perhaps by half their present height or even more. The roses can also wait until spring. Hope this helps.

  14. avis pitkow says:

    Hi Ruth,
    I hope you can help me with this problem which is destroying many of my plants some of which I have had for years. I have a terrible SCALE problem. I am about to lose a large pencil cactus and have lost countless begonias from what appears to also be scale. I have read everything on how to get rid of them but I have not had much success. At present I am using a horticultural oil (neem) and it helps some plants but not others. I need help or everything will be done in. I am also one of those people who sets up hospital settings for my ailing plants and really hate to give up. That’s probably why the scale infestation became so intense.
    Anyway, any and all help will be gratefully accepted.
    Thank you.

  15. Hi Sandy,
    I live in Southern Illinois 6-7 and purchased a Gardenia tree early last year. It had some blooms and buds, blooms opened and smelled great, buds all dropped. Late in the fall while bringing it in (leaves were starting to fall) I dropped the pot along with myself. Well I put it right side up in the pot and put it in my laundry room which has a sun tunnel. I now have small green leaves but some have started to have brown tips.
    Should I fertilize it? Move to morning sun? Use a bug-be-gone spray? I don’t see any creepy crawlers. Help.

  16. A comment for Helen. My Hydrangea was lush with great leaves but no blooms. A friend said her Dad always took a spade and dug around it, about foot out, deep enough to cut some roots. Said the plant will think your trying to get rid of it and start producing flowers. Mine sure did and it has now bloomed two years in a row. Strange but it worked.

  17. Ginger Y. says:

    I have a “Golden Nectar” plum. The tree was planted in 1993 but for the last 9-10 years there is a hole in the fruit near the pit. The fruit is not misshapen. The pit is not split, as was previously suggested to me. The area around the hole never ripens; it is always very firm. Can you figure out what to do to get rid of the hole? BTW, I live in the Bay Area I sent you a message on your face book page. I included a picture of the problem. I tired to figure out a way to attach a picture on this site; but I couldn’t figure out how.
    Thanks, Ginger

  18. Ruth Rogers Clausen says:

    Hi Avis,
    So sorry to hear about your scale problems. I hope you will be able to get them under control. Where you can, try to scrape them off very gently with your fingers, with a Q-tip soaked with rubbing alcohol, or even a pair of tweezers. Glad the neem is giving you some results. There are many products advertised as remedies for scale, but don’t overdo it. It will take some time to control. I also like to give the plants a good shower every few weeks to discourage bugs of all sorts—be especially vigilant about the undersides of the leaves and at the nodes ( where the leaves join the stem). If you repot, throw out the soil from any pot in which the previous occupant was infected and clean the pot thoroughly if you reuse it. Sanitation is critical, so if you end up having to remove leaves with scale on them, be sure they get added to the trash not put on the compost pile. You are wise to isolate infected plants. As a last resort, take cuttings from your established plants and be certain that they are not infected or have been cleaned. Dump the mother plants. Good luck.

  19. Ruth Rogers Clausen says:

    Hi Sandy,
    You must have been disappointed to lose all the buds from your gardenia. It was probably suffering from too low humidity. Try misting the plant daily and keep it away from heat sources or drafts. When you water, give the soil a real soaking—I put mine in a bucket of water to cover the soil level. When it is thoroughly soaked it will stop bubbling. Allow it to drain before returning to its spot. I also put my plants in the shower (cool water with a gentle spray) every week or so. This helps quite a bit. Don’t fertilize at this point, until you see some good strong new growth. Leave it where it is. Avoid chemical sprays until you really need one. Hope you get some nice blooms this year.

  20. Ruth Rogers Clausen says:

    Hi Susan,
    If your friend’s Dad had good results with his methods of forcing bloom on the hydrangeas, more power to him! I expect that the bushes were trimmed in Fall after bloom time or the expected bloom time. Most hydrangeas actually develop their flower buds for the following season right at bloom time, so if the plants are trimmed then, the following year’s flower buds get removed. As long as your bushes appear healthy avoid cutting them back. You should get blooms the following year.

  21. Karen Novak says:

    We have a large (6′-8′ ft tall) burning bush on the corner of our house. We want to trim it back to about half so that with new growth it will be the height we want for summer. It is February in Pennsylvania now, and we are having a week of 60 degrees weather. I would like to prune it now before it gets busy with all the gardening of spring. Is it an ok time to do it, and do you have any other suggestions about pruning it? The base of it is very close to the house…do you know if we have to worry about the roots digging into the foundation of the house? Thank you!!

  22. Karen Novak says:

    We have a large (6′-8′ ft tall) burning bush on the corner of our house. The base of it is very close to the house…do you know if we have to worry about the roots digging into the foundation of the house? Thank you!!

  23. Ruth Rogers Clausen says:

    Hi Karen,
    You must be very anxious about the burning bush (Euonymus alatus) to have written twice! No worries. Yes, you can give it a good cut back now before it starts into new growth for the season. Take some of the older stems back all the way to the ground to thin it out and allow some air movement. Take out those closest to the house first. Stems may be very thick, so you will need a pruning saw (they are not expensive—get one that folds which is convenient). After it is thinned a bit, then cut the top back—ideally 1/3 this year and more next year to avoid too much shock. I suggest you cut at differing heights so you don’t end up with a very ugly straight horizontal line. You should not have trouble with roots in the house foundation. Enjoy!

  24. Karen Novak says:

    Thank you for your detailed reply…it is very helpful! Greatly appreciated! I’m glad to
    know that I can get a head start on yard work.

  25. I have 2 large, black containers on my shady front porch (covered). However, it receives the afternoon sun from about 3pm on. Will caladiums survive the afternoon sun/heat? I would appreciate any suggestions for achieving some curb appeal. Thanks.T

  26. Deborah Bowie says:

    Hi Ruth, I had a problem last summer with leaf hopper insects on all my container plants. Do I need to clean my pots with anything special before I use the containers this spring and if they do come back is there an environmentally safe insecticide I can use? Our zone at our camp is 3-4.

  27. Ruth Rogers Clausen says:

    Hi June,
    The large black containers sound nice in the shade. Can you move them at all in the afternoon so they don’t get baked? By 3pm the sun shouldn’t be as intense.. You don’t say where you are located. I’d be inclined to give it a shot. If they appear to be burning at all, move them more shade.I wonder which is you favorite caladium. Mine is ‘Fire & ice’!

  28. Ruth Rogers Clausen says:

    Leafhoppers are found almost everywhere and cause a lot of damage to leaves as they suck the sap, usually from cells on the user surface of the leaf.. There are several species, some specific to various crops. Usually they leave white dots on the leaves and scat on the undersides. They are preyed upon by lady beetles, lacewings, and spiders.They can be controlled with sticky traps, row cover, or insecticidal soap. Definitely clean the pots thoroughly before replanting. Dip the pots, soaking them in a solution of 1 part bleach to 9parts water, then let them air dry. Make sure that the soil you use to pot up the pants s not infected from last year. It is wise to obtain new soil for potting

  29. Thank you so much for your quick reply, Ruth. I will definitely follow your recommendations!

  30. No matter how I’ve tried to hit just the right timing for the pruning of my lilacs, mock orange and hydrangeas, it seems wrong, since I end up with virtually no blooms the next year. I inherited some 15’+ lilacs, and while I’ve managed to reduce that down to about 6′, there are a lot of suckers, and, as I said, a dramatic reduction in bloom. Do you have a more specific indicator of the right time (blooms are still on, but brown, or have dropped, or?) I do live in the Sierra foothills in CA, where we’ve had drought before and floods this year, but I don’t know how much that makes a difference. My shrubs & I thank you in advance….

  31. Ruth Rogers Clausen says:

    Hi Holly,
    Timing is everything in pruning shrubs. As for the lilacs I would remove the suckers that are probably coming from the rootstock. Prune immediately after bloom time, taking about 1/3rd of the older stems to the ground. If the shrub is already thin, leave a little more. This will encourage new growth that will take a couple of years to bloom. The stems that you leave can be pruned back as well by about 1/3. They will set new flower buds for next years display. Keep the shrubs from drying out as best you can. Mock orange and most hydrangeas should also be pruned right after bloom time.

  32. Julia Brine says:

    I was given a handful of Amaryllis seeds. Will they grow into plants? What should I do with them? Thanks, Julia

  33. I didn’t get all of my tulips planted in time last fall. I put them in a paper bag in a refrigerator
    over winter. Can I plant them outside now (May 4th) , or wait till fall. I live in Minnesota.

  34. Maureen workman says:

    I have lots of perennials and I mark them with plant sticks. I use extreme sharpie but the print fades. We have all four seasons in New Hampshire. Any suggestions for a different marker?

  35. Can you suggest a way to keep my Peony blooms from falling over? Should I be doing something preventative in the early spring? I live in northern Delaware and all my year-old plants are starting to bloom now.

    Thanks for your help,

  36. Ruth Rogers Clausen says:

    Hi Julia,
    Sure your amaryllis seeds should grow into plants but no guarantees depending upon how old they are and how they have been stored. I suggest holding the seed in the fridge until you can plant them. Some people recommend floating the seed on water until they germinate and then pot up individually. Otherwise sow them as you would any other seed in a seed starting mix that drains well. Cover seeds lightly, firm them in, and water gently. The soil should be kept moist (cover the container with a piece of glass or plexiglass). Bottom head speeds up germination or put the container in a shaded place outdoors through the summer.
    Germination usually takes about 3 weeks. Pot them individually as soon as they are big enough to handle. Hope you’ll give it a shot!.

  37. Ruth Rogers Clausen says:

    Hi Geri,
    If the tulip bulbs were mine, I would get them in the ground now as they may well rot by fall. Don’t bother planting any that are soft and maybe rotten now. At best they should leaf out this year but it’s doubtful if there will be any flowers. If you feed them with 1/2 strength liquid fertilizer through the growing season you have a good chance of flowers next year. Good luck!

  38. Ruth Rogers Clausen says:

    Hello Maureen,
    You have hit on a perennial problem! The Brothers P-touch PT-H100 Easy, Handheld Label maker works well. My friend Holly Shimizu (AHS) uses Black Print on White Tape, Compatible with Machines that use 1/2 inch TZ Tapes. She also buys different size metal garden labels from the Everlast Label Company ( I hope you will try this, although there may be a small learning curve.

  39. Ruth Rogers Clausen says:

    Hi Suzie,
    Doesn’t it seem that heavy rain comes every year just as the peonies are peaking?! I like to put heavy duty peony rings round my plants as soon as the buds break ground. Many people leave them in place year round. Get the best quality you can find. is a reliable mail order company. (search for ‘peony guards’). Some people make a ‘cat’s cradle’ using bamboos; others use large tomato cages. The secret is to stake BEFORE the stems flop. Enjoy as cut flowers if they flop!

  40. Maureen Davis says:

    Hi Ruth,

    Thistle invaded my front flower bed about 10 years ago and it feels like I spend half of my life pulling up thistle. I don’t like to use chemical weed killers. Other than completely destroying my flower bed with black plastic is there any other way to rid my garden of these tenacious invaders?

  41. Ruth Rogers Clausen says:

    Hi Maureen,
    So sorry to hear about your thistle patch and on-going weed pulling. The problem with PULLING these deep-rooted thugs is that it’s only too easy to remove the top but leave much of the root. Each time you break off the top, the remaining root goes into high gear to regrow. Try to CUT off the stem just above ground level. Paint just the cut stem with herbicide, which will be taken down into the root and kill it. If that is not an option, rather than pulling the plants, dig down alongside each stem as far as you can with a trowel (the narrower the better) to remove as much of the root as possible. Bag & destroy debris—NEVER put on the compost pile. BE VIGILANT about DEADHEADING every last flower that will produce more seeds. Over a couple of years this will work, but be patient. Good luck.

  42. Colleen Robustelli says:

    I have a fair amount of hydrangeas in my yard that have been planted in the last few years. Anything in particular I can do to insure lovely blooms.?Thank you, Colleen Robustelli

  43. Nora Fugate says:

    Hi Ruth,
    I live along the Gulf coast in FL, due west of Tampa. I am growing serrano and fresno chili peppers in pots on my patio and have a white fly issue. I’ve tried neem and then moved on to insecticidal soap, but neither approach seems to help. Any suggestions you could offer would be greatly appreciated!

  44. I have bittersweet and another invasive vine that looks like a virginia creeper – both are equally invasive – I am ripping out as much of both as I can…any other recommendations welcome; also what do you feed lilacs? and apple and plum trees (organic). Thanks

  45. Laura Vance says:

    Hi Ruth,
    We live in central Ohio. We have planted 6′ arborvitaes behind our pool for privacy. There are eight all together. Last year we had to replace three and this year the same three plus one more. We were told at the nursery to plant the ball somewhat above soil level for better drainage. I bought some Holly Tone for evergreens and plan to use around them but not near trunk. Any other suggestions?
    Thanks so much!

  46. Ruth Rogers Clausen says:

    Hi Colleen,
    How nice to have lots of hydrangeas. You don’t say what kind they are. Mopheads? maybe a gift plant with large rounded heads of flowers? Oak leaf type with large, pointed heads of usually white, fading to pink flowers? Smooth (snowball) or panicle ( with cone-shaped heads) hydrangeas both of which have blooms on new wood made this year? All types need to be kept well watered especially during the summer (a mulch of organic compost or shredded leaves is good for this). Pruning however is different. Remove all dead stems at any time. Prune Mopheads right after bloom time to a strong-looking pair of buds removing perhaps 1/3rd of the growth, less if you prefer to have the plants taller. Oak leaved types need little pruning unless they are getting too big. If so prune out 1/4-1/3rd of the older stems to the base in e. spring. The other types can be pruned in late winter just as new growth is beginning. Again, prune to control size or to remove rangy stems, maybe 1/3rd off the top. Always cut just above nice fat buds.

  47. Ruth Rogers Clausen says:

    Hi Nora,
    Whiteflies seem to be a perennial problem with warm weather veggies, especially when the plants are in pots that dry out fast. Keep the plants well-watered and healthy, but avoid extra fertilizer that produces soft, pest-susceptible growth. Just a few suggestions to get rid of them, or at least diminish the population considerably. Try vacuuming them with a hand vacuum when they are disturbed —this may sound silly but it works. Also buy YELLOW sticky traps available at nurseries and hang or position close to the plants. Or cut up pieces of YELLOW poster board and smear with sticky Vaseline or Tanglefoot. The USDA recommends a homemade spray, similar to insecticidal soap:
    Add 1T dishwashing liquid to a cup of vegetable oil and shake well. This is the CONCENTRATE. Add 2T of this to a cup of water, shake well and apply, especially the undersides of the leaves. Repeat every few days.

  48. Ruth Rogers Clausen says:

    You are doing the right thing to rip out invasive vines. I hope you don’t have poison ivy too. If possible trace the vines to ground level and cut there. Dig out the roots or paint the cut surfaces with strong vinegar or herbicide. The tops will die off if not removed.
    Lilacs do not need much feeding. A light application of a high phosphorus product (5-10-5, 5-10-10) in early spring promotes good bloom.
    Give apples and plums a light application of compost in early spring and fork it in gently. When weather warms, apply a 2″-3″ deep summer mulch of compost, shredded leaves, or other organic material to keep soil moist and weeds down.

  49. Ruth Rogers Clausen says:

    Sorry to hear about your arborvitae Laura. Were the plants balled and burped with heavy string I wonder? If so, you must cut the heavy cord that holds the soil together before planting. Otherwise as the plants grow they are strangled by it. Also, plants often arrive with the roots in metal baskets. These too should be removed. Planting slightly high is a good idea, but does not replace preparing the soil properly and ascertaining that drainage is good. Almost daily watering is essential to maintain soil moisture in hot Ohio summers. Refrain from fertilizing until the plants look healthy. If possible have someone from the nursery or from Cooperative Extension (usually listed under Government offices in phone book) come to inspect them. You could also send pictures to them.

  50. Laura Vance says:

    Thank you Ruth! I think the problem was that we did not water them enough. We watered less because the nursery told us our other ones probably died because we planted too low and then watered too much and so didn’t drain well enough. I think I may purchase a soaker hose and see what happens.

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