Climate is What We Expect;
Weather is What We Get*

– Posted in: Garden chores, Weather, What's up/blooming
23 comments

image of trees just leafing out

We usually see the trees budding in early May, not early April

The weather has been unseasonably warm here. It’s a great cure for cabin fever, but a worry to the true gardener. If it’s this warm and dry in early spring, what will July be like? It also incites the gambling tendencies inherent in our noble profession. I wonder if we’ve had our last frost? (Not hardly.) To combat both the anxiety and the recklessness that a warm and dry spring arouses, I find it very helpful to put a little phenology to work.

Phenology? What’s That?

Phenology, if you’ve never come across the term, is the science (or perhaps art) of tracking natural occurrences and changes over a long period of time, to discover the patterns and rhythm of them, in order to learn from them. It is one of many good reasons to keep a garden notebook, so you can develop an accurate phenology of your own unique ecosystem.

When You Hear the Peepers, Plant Peas

image of Cornelian cherry in foreground, Juneberry in background

A sight I never thought I'd see: Cornelian cherry and Juneberry blooming at the same time.

So we are planting our peas earlier than usual, because the peepers started peeping earlier than usual. What the peepers actually tell us, I think, is that the soil temperature has warmed sufficiently for them to come out of hibernation. Soil temperature is a good indicator of when to plant, as the soil warms up much less quickly than the air, and a week of unseasonably warm weather doesn’t affect it quite as much. But the indicators that are strongly affected by air temperature are not as reliable during abnormally warm weather. For example, my Cornelian cherry usually blooms about three weeks before the forsythia. This year it beat the forsythia by one measly day. The Juneberries, aka as shadbush, usually bloom in May. They’re already blooming, sadly. (The month of May could be bereft of May flowers.)

Develop Your Own Very Local Phenology

I didn’t have any garden to-do’s associated with the Cornelian cherry, the forsythia, or the Juneberries, so they’re not messing me up. I do have a good idea of when our last frost is, and counting back from that is probably still the best guide to when to plant things. Of course, the more years you’ve been gardening in the same place, and recording this date, the more accurate you will be. Nature Calendar is an interesting phenological source for those of us in hardiness zones 4-7, east of the Mississippi. If you haven’t spent much time in your present garden, it can help you pinpoint where you are in the cycle of seasons. You can also peruse an earlier post I wrote on phenology, which had observations I had collected from a variety of sources. It frustrated me then, and still does, that many of these maxims either do not agree, or are not precise enough to be helpful. But if you have nothing to go on, they can be a good place to start.

Do you use phenology to direct your vegetable garden planting, or guide you in other garden chores? I’d be interested to hear of your observations.

UPDATE: Just discovered the USA National Phenology Network.

*Quote attributed to Mark Twain

About the Author

Kathy Purdy is a colchicum evangelist, converting unsuspecting gardeners into colchicophiles. She would be delighted to speak to your group about colchicums or other gardening topics. Kathy’s been writing since 4th grade, gardening since high school, and blogging since 2002.

Autumn is a second spring when every leaf is a flower.

~Albert Camus in Albert Camus quotations

Comments on this entry are closed.

Mary April 18, 2010, 7:17 pm

I have had a Forsythia bush out front for years & yes it bloomed early this year (northern Michigan) & it’s sooo beautiful…but I forget & that’s why I’m posting: how long do the blooms last usually? Does it bloom again later in the year or just the once? Seems like I’ve seen the leaves a pretty deep red or purple in the fall, am I correct? Thanks, Mary

Kathy Purdy April 18, 2010, 7:20 pm

It usually blooms just once, although sometimes you get an occasional flower or two in autumn. How long the blooms last depends on the weather. Cooler weather means they last longer. I doubt more than two weeks, however. Some people report deep red or purple fall color. I think it depends on the variety and, again, on the weather.

tangledbranches April 17, 2010, 7:53 am

Thanks so much for that link to Nature Calendar. That’s exactly the kind of thing I’d like to do for myself (except my notes are too haphazard). Now at least I can benefit from the observations of someone else.
.-= tangledbranches´s last blog ..Garden Bloggers’ Bloom Day =-.

A.R.Wadoo April 15, 2010, 1:24 pm

The unexpected change in the climate has brought in some new guests to our garden. Birds which had not visited in the past, Iwould love to know the name of the bird. I have photographed the bird .

VW April 14, 2010, 1:12 pm

I was thinking that same thing about “maybe the frosts are over since it’s been so warm this year”. But I didn’t give in to the temptation to kill some baby plants by putting them out too early. At least, not yet. May 15 is our typical frost-free date, and I’ll probably cheat a little if the 10-day report looks good on May 5.
.-= VW´s last blog ..What are Gardeners to Rocks and Mountains? =-.

commonweeder April 14, 2010, 9:41 am

I’ve always been fascinated by the idea of phenology, but never really used it. I know that lilacs are one of the important indicator plants – put in peas when the leaves are as big as a mouse’s ear. I did, but it didn’t really have anything to do with the lilacs advice. I had time. We’ve had peepers already too. We had a hot spell, but we are back to the usual April tempertures – and rain – for now.
.-= commonweeder´s last blog ..More About Containers =-.

Gail April 13, 2010, 9:08 pm

Kathy, I have only begun to keep records, but my photo archives show me that bloom time is off for many plants…We had a colder then usual late winter and now a warmer then usual spring..I can only imagine what the summer will be like! This variability is what Climate Change is all about. gail

Layanee April 12, 2010, 8:40 pm

Ideally I would pay attention to the signs but I usually plant when I have time. I mentioned just the other day how unusual it was to see the shadblow blooming along with many other spring bloomers. A bit disturbing.

Sylvana April 12, 2010, 4:07 pm

My bulbs are a full month early, but my flowering trees/shrubs seem to be nearly on time.
I am a little concerned about what the weather will be this summer. We couldn’t possibly luck out and get two cool summers in a row.
.-= Sylvana´s last blog ..More Stuff That Made It, and a Wee Treat =-.

Diana April 12, 2010, 12:19 pm

So interesting, isn’t it? I’m not very good at detailed observations like you are, but my blog really helps me compare more major events from year to year. We’re about 3-4 weeks behind in Central TX for most things, but our frigid winter didn’t actually kill much, which has surprised most gardeners. And yes, I DO worry with our 10 degrees warmer than normal spring, what July will hold!

Melanie Watts April 12, 2010, 12:05 pm

I think phenology is one of the better ways to decide what to plant when. There is still snow in my garden so I know it is way to early to plant anything.

melanie Watts April 12, 2010, 12:02 pm

I think phenology is one of the better ways to decide what to plant when. Spring is a lot shorter in zone 2 and 3 so planting isn’t so long and drawn out although this year it spring is longer than usual. I still have snow in my garden so I know it is way to early to plant anything.

A.R.Wadoo April 11, 2010, 11:14 am

Kathy on April
But me on March
I was worried in March when the temperature in our cool valley jumped to 15 degrees above normal. It was dry and hot .Every bulb bush and the tree started blooming. We had to irrigate the annuals and the tulip bulbs.It was a sure sign of climate change “The Global worming”.But dear April brought the rains and the old cool climate which contines even now. The blooms on the trees have lingered for, much more time, than normal. The fate of the expected fruit needs to be seen and recorded.
Kathy u are right phenology needs to be rewritten under these circumstances.

Sue April 11, 2010, 6:26 am

The Forsythia here in NORTHERN Michigan are in full bloom. I checked my journals for the past 3 years and that is a FULL month early. My lilacs and fruit trees are all leafing out. Way way too early. I’m holding off on planting…….our typical last frost date is June 1. But, I admit, it’s very hard not to be tempted.

Craig @ Ellis Hollow April 10, 2010, 9:23 pm

One of our faculty in the Dept. of Horticulture at Cornell, David Wolfe, is an authority on climate change and its impacts on agriculture. He did some oft-sited phenology studies looking at bloom times of lilacs, grapes and apples in the Northeast. (See abstract here: http://adsabs.harvard.edu/abs/2005IJBm…49..303W )

Bottomline:

“Collectively, these results indicate an advance in spring phenology ranging from 2 to 8 days for these woody perennials in northeastern USA for the period 1965 to 2001, qualitatively consistent with a warming trend, and consistent with phenology shifts reported for other mid- and high-latitude regions.”

Anyone think it’s cooled off since 2001? Know any fruit growers? They’re real concerned that early flowering might be setting them up for damage from late freezes.
.-= Craig @ Ellis Hollow´s last blog ..Fritillaria raddeana =-.

Jen April 10, 2010, 6:45 pm

I had the same thought about no flowers in May! I have tulips blooming and more on the verge of blooming. Of course I can’t remember if any of them are early spring varieties, but still…it seems all so strange..

Sheryl at Providence Acres Farm April 10, 2010, 6:39 pm

It is a warm and early spring this year but I am not taking any chances with my tender veggies.
.-= Sheryl at Providence Acres Farm´s last blog ..A Surprise Addition to Our Family =-.

Annie in Austin April 10, 2010, 6:11 pm

Love this topic, Kathy – remember Henry Mitchell writing about the signs in Washington, DC.
When we lived in IL the saying was that when lilacs bloomed and the maple leaves were expanding you were pretty safe from frost. I don’t know if that holds true anymore since the lilacs of family members up there froze not too long ago.
For the last 3 years making bloom lists for Carol has helped me notice when certain plants bud but that’s too short a time for a real pattern. Down here in Central TX you’d think I could count on a native plant, but I’ve had to run out and cover them, too. After growing them for 10 years at 2 Austin houses, the surest signal of no more frosts & time to plant peppers here seems to be the emergence of the totally non-native Balloon flower stems!

Annie at the Transplantable Rose
.-= Annie in Austin´s last blog ..A New Song for Wildflower Time! =-.

Benjamin April 10, 2010, 5:43 pm

Same in Nebraska. Way warm, way early. Everyone says I’m crazy, but we are two weeks early–crabapples don’t bloom this time of year!
.-= Benjamin´s last blog ..I Know Nutting! =-.

Dee @ Red Dirt Ramblings April 10, 2010, 4:27 pm

Kathy, this is wonderful information. I never hear about phrenology before. Thank you.~~Dee

Kathy Purdy April 10, 2010, 4:33 pm

Dee, check your spelling. I’m talking about phenology. Phrenology is something else.

Mr. McGregor's Daughter April 10, 2010, 4:14 pm

I’m also worried that it’s going to be a very hot summer. Global warming naysayers, eat my pollen. Things are so early & out of whack here.
.-= Mr. McGregor’s Daughter´s last blog ..Don’t Blink… =-.

Carol April 10, 2010, 4:14 pm

I don’t know if it is true phenology, but I always plant my peas on March 17th. I’ve checked the soil temperature on that day for a few years in a row and it is always warm enough.
.-= Carol´s last blog ..Violets =-.