Viburnum - "Winterthur" and "Black Haw" - where to plant?

Plainfield, NJ

I just bought "Winterthur" and "Black Haw" Viburnum from my local nursery who assured me they would pollinate each other. I'm wondering how close together I must plant them - the 2 sites I have in mind are about 12 feet apart with nothing in between except an expanse of grass. A few other shrubs are nearby, but not directly in between these 2 locations I have in mind. Would putting the 2 viburnums there be close together enough for birds, bees, and the wind do the pollination work?
Thanks in advance,

Elgin, IL(Zone 5a)

Viburnum Valley is definitely your expert here - I can just give you my observations.

I grew a "Black Haw" approximately 25 feet west of a viburnum opulus compactum and a viburnum trilobum compactum. Between the latter two and the viburnum prunifolium were a huge crabapple (20 feet tall and 15 feet wide) and a cotinus 'Grace' smokebush (15 feet tall and 8 feet wide). I experienced spectacular displays on all three viburnums. Honestly, I didn't even know that viburnums required pollinators. I just loved them so much that I apparently had enough, and was lucky enough, to have lots of different ones that apparently pollinated each other.

But again, this is anecdotal. I'm Sure that VV will give you a more scientific perspective and a definitive answer.

suburban K.C., MO(Zone 6a)

I have one Persimmon tree and it is dioecious, (not self fruiting) and it has Persimmons this year, it was a sapling in 2005. Anyway, I suspect bees pollinated it, I only have 1 Persimmon tree and I don't know of another one around here that might've pollinated it. I know bees are on their way out because of pesticides used in crops. I'm not sure why it say BAYER: save the bees! actually, because it's them that manufactures the pesticide, I'm sure it's just a mix-up at the Avaaz site. I have been signed up with Avaaz for a couple years. I thought about 400 feet was the distance between pollinating plants myself.
Good luck Jan, I too bet VV can tell you.

Plainfield, NJ

Thanks folks. I just sent a private email to Viburnum Valley. As for bees, I love bees in my garden. We make a point of planting things that bees love and we have lots of bees in our yard - our Butterfly Bushes and Joe Pye Weed, for example, are usually full of bees.

Scott County, KY(Zone 5b)

Wow - I want to know the name of that nursery, and warn all New Jerseyians (-ites?) to badger them about their plant knowledge.

Viburnum prunifolium (Blackhaw Viburnum) and Viburnum nudum 'Winterthur' (Possumhaw Viburnum) don't even overlap in bloom time. Think about that. Viburnums are good, but they aren't magicians.

I don't think they would pollinate each other anyway, since they are not very closely related species. You will need another "flavor" of Viburnum nudum (like 'Brandywine') to cross pollinate with 'Winterthur'. It is possible that the two Blackhaw Viburnum you have are not identical clones, so they should cross pollinate each other. If - after flowering next spring - you do not have heavy amounts of fruit forming on your Blackhaws, then finding another one of them might be in order.

If you have a typical quarter acre lot, like many residential properties, anywhere on the site will be fine for pollination purposes. Closer is always easier for the fauna involved.

Wind does not provide pollination for Viburnums, nor do birds. Birds eat the fruit and deposit them wherever, and you can get easy seedlings this way. Insects provide the pollination action - bees and other small winged friends. Watch your plants in bloom next year, and see what variety of bugs show up to do the job.

Good luck in the endeavor - you can never grow too many viburnums...

Plainfield, NJ

Oh sh**t. I could buy a third Viburnum and hope, if I plant it now, it'll settle in before the weather gets too cold.
Hey, if I pinch back some buds next spring, can I delay the bloom time on one Viburnum and force them into sync?
Thanks for the advice, altho it's not what I was hoping to hear.
The nursery is Barton's in Edison. Usually I'm very happy with them, and the staff seems knowledgeable, but I don't know enough to assess that. If they tell me something wrong, I wouldn't know.

OOPs, I just realized if they're the wrong variety for cross-pollination, even if I delayed the bloom on one of them, it still won't work.

This message was edited Oct 5, 2012 12:07 PM

Scott County, KY(Zone 5b)

Read up more on Viburnum. You can't treat most woody plants like a perennial or annual herbaceous plant (pinching back).

Most viburnums set their flower buds on old wood, from the previous growing season. By "pinching back" you will only be removing all chance of flowers for that season - not the result you are after.

To delay flowering on woody plants, you should keep them in cold storage to delay breaking dormancy. How big is your cooler?

Tell your friends at the nursery that they ought to provide you with the appropriate pollinator for the plants you purchased, and post a great big mea culpa to all the rest of their customers. They'll reap scads more in positive press by doing right by you and others.

In the name of accuracy, I looked up my bloom charts and records for the species in question. Viburnum prunifolium and its clones typically wrap up bloom by the second week of May. Viburnum nudum and its clones don't start bloom till the first week of June. These records are for Scott County, KY which is solid zone 6. I'd expect similar symmetry for NJ.

Elgin, IL(Zone 5a)

Really good reading, Viburnum Valley. I remember wondering whether I needed to deadhead the flowers on all of my viburnums when they were first installed. When I asked an expert and he said no, I was thrilled. I had a lot of viburnums.

I have pictures of my prunifolium in full bloom on May 27, 2011, but I think that may have been unusual. 2012 certainly was. I saw all kinds of bizarre variances last year.

And conditions can be atypical in a single year. I believe you pointed this out to me on a thread years ago. I had five huge viburnum plicatum tomentosum "Lanarth". Until a single winter wiped them all out. They were supposedly zone 5a hardy. After a good cry, I adopted my philosophy that a loss represents an opportunity to try something different and new. Enormous zone 4 roses. A single Constance Spry, which had been too large to place in my garden before.This is where two of them were situated.

There is nothing like viburnums, but it gave me considerable solace.

This message was edited Oct 8, 2012 6:52 AM

Thumbnail by DonnaMack
Scott County, KY(Zone 5b)

Good comments, DonnaMack.

Remember: I am in central KY, which is solid zone 6 and sometimes (historically, up through 1994) zone 5a. I will always have plants go through their paces before anyone in northern IL, probably about 2 weeks earlier on average.

What is important to remember: the order of things will not change, regardless of the exact date. If Blackhaw Viburnum blooms 3-4 weeks ahead of Possumhaw Viburnum here, then it will behave the same way in northern IL, or NJ, or the Pacific Northwest.

Plainfield, NJ

I called the nursery and told them I need to exchange the Blackhaw for one that will pollinate the Winterthur which I'd like to keep. They seem eager to do the right thing and I'm waiting to hear back - the most knowledgeable guy, the owner, is not in every day, hence the delay. The employee said if they don't have the right virburnum in stock, they can order it for me once they find out what will pollinate the Winterthur. I just hope this is straightened out before it becomes too cold to plant.
Anyhow, thanks folks for your input.

Plainfield, NJ

The nursery is obtaining a Brandywine for me, definitely is a good partner for Winterthur. They'll have it for me tomorrow so I can go exchange the Blackhaw for that. I'm happy with this resolution, it took a bit of time but hey, stuff happens.
- Jan

suburban K.C., MO(Zone 6a)

Wow, Jan, that's great! Kudos to that nursery for doing the right thing, and VV for being so helpful with the knowledge.

Scott County, KY(Zone 5b)

Glad that you achieved an amicable resolution, Jan. Successful gardening begets additional endeavors. That's what it's all about, really.

Send us updates next year; we'll expect seriously heavy flowering and fruiting.

You should have good performance from both of your V. nudum; here is 'Winterthur':

1. in flower
2. maturing multicolored fruit in a park shrub border
3. mature dark blue fruit in a shrub border
4. typical fall color at the Valley
5. winter form with persistent blue fruit

Thumbnail by ViburnumValley Thumbnail by ViburnumValley Thumbnail by ViburnumValley Thumbnail by ViburnumValley Thumbnail by ViburnumValley

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