We’re well into gardening season and you may have some questions. For answers, turn to Ask an Expert, an online question-and-answer tool from Oregon State University’s Extension Service. OSU Extension faculty and Master Gardeners reply to queries within two business days, usually less. To ask a question, simply go to the OSU Extension website, type it in and include the county where you live. Here are some questions asked by other gardeners. What’s yours?
Q: Our mature saucer magnolia (Magnolia soulangeana) tree is having a second bloom cycle. It has an abnormally high number of blooms covering the tree. It started at the top and is working down. It also seems to have many more large buds that seem days away from opening. They are slightly smaller and shorter-lived blooms than springtime.
The tree is adjacent to a large concrete driveway that heated up excessively during the heat dome occurrence. The tree itself is very healthy and pushing growth. Two questions: '
Is this extra bloom cycle coming at expense of next year’s blooms?
Will fresh new excessive growth harden in time to avoid heavy freeze damage? – Multnomah County
A: The basic answer to your question about the magnolia blooming a second time and new growth appearing now is “time will tell.” The heat dome was extraordinary and the coming winter may also be unusual. There is nothing you can do now to either speed up the new foliage hardening off, or change the spring blooming level.
The Oregon State Landscape Plants page for your tree, here, lists it as hardy in zone 5 and even 4. You are likely in zone 8, so frost damage isn’t expected, but it can occur on tender new growth if cold is extreme or occurs unusually early, late, or with drying winds.
Blooming again in the year is termed “remontant” flowering. Enjoy it now, and realize there might be fewer blooms next spring.
Here’s a quote from an Ohio State blog node1376, “A downside of remontant blooms is a slight reduction in overall flower numbers for the next year’s floral display, depending on the number of flowers that actually bloomed out of season. Rarely will remontant plants be totally without any flowers during their typical bloom time. So, just get out there and enjoy that “wacky, blooming plant.” – Jacki Dougan, OSU Extension Master Gardener
Hemlock heat damageOSU Extension Service
Q: The weeping hemlocks in our front, south-facing yard have an alarming number of brown needles. I see one spider web, but don’t think spider mites are the problem because the web is in just one area and the brown needles are in many areas. The needles that are affected the most are on the top of the plant. However, there are some branches were the needle group at the tip of the branch is brown.
Was it the hot, dry weather? A combo? What are your recommendations for next steps? If this is a disease/bug, could it affect other plants in my yard? – Marion County
A: This looks like classic heat damage based on the pattern and appearance of the dead needles. At this point you should give it good TLC to help the shrub pull through the rest of the hot, dry summer. Check your irrigation system and make sure the root zone is getting adequate moisture. Give a little extra attention to watering this week as it is going to be in the upper 90s.
Also, consider shading the plant during the hottest part of the day. You can purchase shade cloth from a garden center or even use a patio umbrella or bed sheets – anything held above the foliage to deflect the direct sun.
Here is some info that you might find helpful. It’s on hydrangeas but has good general plant recovery info that you can use. – Brooke Edmunds, OSU Extension horticulturist
Daylilly flower budsOSU Extension Service
Q: My daylilies and marionberries for two years have had deformed flower buds. This year I picked them off as I saw it happening and destroyed them. It helped, but what is it in the first place? How to stop it from recurring? – Clatsop County
A: Both of these could be due to botrytis gray mold. It can occur when plants are wet for six to 12 hours and temperatures are between 50-65 degrees F – day or night. Flowers and/or buds develop tan or brown sections. Here is some information.
The following cultural controls are recommended:
- Improve air circulation around plants
- Water on surface only
- Remove and destroy flowers and buds showing symptoms
- Clean up and remove plant debris at end of season to help remove overwintering spores
- For raspberries, consider the use of a fungicide like Bonide Captan 50WP (always follow all label instructions)
- For daylilies, at the first sign of infection, consider the use of a fungicide like Bonide Fung-onil Multi-Purpose Fungicide (always follow all label instructions).
There is another possibility for the daylily symptoms – the daylily gall midge. While the foliage of the daylily can be lush, the buds can become infested with the larvae of the daylily gall midge. The larvae are semi-transparent, white, legless maggots that grow up to 3 mm long. Alluding to the pest’s common name, the midge overwinters in the soil with the adults emerging during May-June, when the greyish-brown female fly lays eggs on the developing flower buds of the daylilies. Flower buds infected by this fly can host hundreds of tiny larvae that, from within, chew up the bud causing it to become uncharacteristically squat and swollen. The affected buds fail to open and either dry up or rot. The internal petals of the buds can be abnormally swollen and crinkled. After feeding on the buds, the larvae leave the buds returning to the soil where they overwinter inside silk cocoons.
To try to verify if this is the gall midge, you can collect the effected buds into a sealed bag or container. Wait to see if the tiny maggots exit the bud. Dispose of the sealed bag or container into the garbage. By doing that. you will disrupt this pest’s life cycle. Do not compost infested buds.
Here is some additional information from Washington State Extension. – Bill Hutmacher, OSU Extension Master Gardener
CotinusOSU Extension Service
Q: My multi-stemmed smoke tree (Cotinus obovate), which has been in the ground three years, has developed on one stem a die-back from the base toward the meristem of the sub-laterals in the course of three days. The rest of the small and young tree appears normal. It is planted in a rock-mulched area. There was no evidence of reaction to the extreme heat in June and it was putting on new growth. And a PMJ rhody has also developed die back on ½ of the very young plant about 2 years old planted in the ground this past winter. I hesitate to cut out the dying parts.
Another PMJ totally succumbed and I checked the roots. In my opinion the roots looked dead. Both PMJ rhodies had recovered from the extreme heat and were showing new growth. – Lane County
A: The American smoke tree (Cotinus obovatus) is usually quite sturdy. It does not tolerate wet soil or mulch touching the stems. Unfortunately, a sudden die-back does often indicate verticillium wilt, a disease of the vascular system. Short of girdling damage that would usually be the answer.
As to the PMJ rhody, the picture does look like excess heat damage. Many rhodies were damaged in the last heat wave and now we have another on the way this week. Set up a shade cloth over the young plants, an umbrella, a sheet held away from the plant by stakes, etc. Be sure these plants are well-watered in the morning this week to get past the temperatures in the high 90s to 100s.
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July 31, 2021 at 09:30PM
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Time will tell if ‘wacky’ extra blooming magnolia shows fewer flowers next year: Ask an expert - OregonLive
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