Category Archives: Propagating & Pruning

propagation & pruning

Tip: It’s time to pinch!

chrysanthemum_octoberglory

Chrysanthemum ‘October Glory’

You may have already done this, but if not, now is  the time. In order to encourage many more  flowering shoots from perennial Chrysanthemums, pinch back stems to 4-6″ at the beginning of July. This encourages more stems to shoot resulting in many more blossoms, and perhaps tidier plants. (Of course, if you prefer the blousy look of tall stems that billow forth, by all means leave your plants be.)

mumcutback

On the left are a few budded shoots but there could have been many more…on the right, ‘Hannah’s Double White’ with numerous blossoms.

You can also cut back the taller fall Asters and their relatives, such as Boltonia, to keep them neater and in proportion to their surrounding neighbors. For example, Aster ‘Vasterival’ reached 5′ last September, and it was just too much Aster for the nearby Caryopteris and perennial mums.

aster_cut

Tall willowy stems of Aster ‘Vasterival’ before cut back, and in flower.

Spring Succulent Rehab

agreendrum2_fall2016

Remember your gorgeous succulent containers from last summer? Did you take the time to bring in and care for all those tender
plants over the winter? And, now, do they look overgrown and leggy, or a little scruffy to say the least? You have company…mine do too! Here are some suggestions on what to do to give these babies a new lease on life.

echeveriaset

Give your succulents some fresh soil!

First, give your succulents some fresh soil for new roots to grab into. Remember to use a sharp draining mix formulated for succulents…a basic everyday potting soil will stay too moist. Loosen up the roots, and shake off some of the old soil. Remove any old browning leaves that still cling to the lower stem. Repot in the same pot or a pot that is slightly larger.

If you are rehabbing a large container of mixed succulents that were part of an ensemble and want to give it new life, unplant everything and do the same thing. You can top dress the soil with a fine gravel, chicken grit or uncolored aquarium sand, which will prevent low lying foliage from staying in constant contact with moist soil.

Rosette forming succulents often elongate during short winter days and low indoor light, or they may just be prone to doing so anyway, with age. You might like to have the height that tall gangly stem offers, and if so, just leave the plant be. On the other hand you may want to offset the top heaviness. There are a couple of options.

aeonium1set

Aeonium with aerial roots….

Option 1:  Bury Her. Notice that a lot of bracing aerial roots have developed along the stem of this Aeonium ‘Cyclops’. Last year I tried this unorthodox remedy. I found a deep clay container and replanted the Aeonium low in the pot. Succulent soil mix was used  in the lower half, but then I topped the upper pot portion with perlite. This allowed good aeration for new roots to develop off the main stem.

aeonium2

Option 2: Off with her head! This may cause you to hesitate, but you will have to cut off the  Aeonium’s top rosette, (you can then root the rosette to form a new plant).  The stalk will hopefully break anew with fresh growth and branch out, but I should warn you this takes a while to happen.  As for that top rosette, let the cut edge air dry for a few days to “heel” or callous over. Then fill an appropriate sized pot with perlite or a mix of perlite and sand, insert the cut end of the rosette into the pot and water frequently.

echeveria_elongated

Echeveria with elongated stem

These methods work for elongated Echeveria too. Repot in a tall tom, or cut off the top rosette and try rooting it. Note: You may or may not be able to encourage side rosettes off that main stalk (depends on what type of Echeveria hybrid it is), but hopefully your rosette will root in to form a new plant.

Mystery Echeveria…purchased as 'Fleur Blanc'

Echeveria ‘Fleur Blanc’

Many succulents bloom in late winter and early spring, and these blooms are quite lovely, as seen above in Echeveria ‘Fleur Blanc’. The blooms often help identify plants that you may have acquired without a proper name.

xsedeveria_mixup (1 of 1)

Look-alikes. x Sedeveria ‘Letitia’ on the left, and ‘Sleepy’ on the right.

For example, these two very similar x Sedeveria are often mixed up in the nursery trade. When not in bloom they do look quite alike.  Now in flower, I can tell that the one on the left is Sedeveria ‘Letitia’ (pale yellow/white) and on the right is Sedeveria ‘Sleepy’ (orange/yellow). Also, notice some plants like these Sedeveria have offsets forming at their base. These offsets can be severed and rooted or potted in small pots if roots have already formed.

cuttingtri0500

Cuttings left to heel, decayed foliage must go, leaves sometimes root too!

Recap:

  • Cut back leggy growth.
  • Let cuttings air dry for a few days to seal the cut ends.
  • Lie or stick in a sand/perlite rooting media.
  • Groom aging  and decaying foliage.
  • Repot all plants in fresh succulent potting soil to give them a new lease on life.
  • Top dress newly potted succulents with fine gravel, aquarium stone, or chicken grit
  • Note (and photograph if you can) what the flowers look like on your plants to confirm their identity.

With longer days and fresh soil, your repotted succulents will show you how happy they are in 4-6 weeks. Once the weather warms, transition plants outdoors on mild days, first in a spot which has just morning sun, and then gradually allow them full day light. Too much strong sunlight on a warm day after plants have been indoors may cause the leaves to get sunburned.

For other posts on Spring Care of Succulents see:

In bloom: Tender Succulents

Rehabbing Succulent Containers

 

 

 

 

Collecting Seed for Seed Exchanges

Clockwise from top left: Cynara cardunculus, Galtonia viridiflora, Talinum  paniculatum

Clockwise from top left: Cynara cardunculus, Galtonia viridiflora, Talinum paniculatum

A few of the various Plant Societies which I belong to have seed exchanges, and I made a pledge to myself to get my seed collecting done, cleaned, sorted and packaged into little envelopes to meet this year’s deadline, which is usually Nov 1.  Time always has a way of getting ahead of you, so I was relieved to learn on the Hardy Plant Society’s webpage that they have extended the deadline this year to Nov 15, and I can fill out the donation forms online and mail the seed in later! The North American Rock Garden Society is not being so lenient; they want the list of seed being donated by Nov 1st, although they will allow a grace period until Dec 1st to package and send your seed in.

Yes, it does take time to process and save seed, but let me tell you why it is worth all the trouble. First, if you want to grow more of the plants, especially the annuals, which you enjoyed in your garden this year, why not collect the seed and save yourself a few dollars. Second, you may not be able to find a particular seed variety next year. I have found this true when it is an unusual variety that commercial growers do in limited numbers, or more likely their source dried up or had a crop failure. Third, you are bound to collect more seed that you can use, so why not  share the bounty by participating in a seed exchange? Most seed exchanges work this way: You become a member of the group, such as the Hardy Plant Society, which collects and pools the seed, then makes the seed available to its membership at a very inexpensive price ($.50). A big plus: seed donors get first dibs at the selection,  and get to select an extra 10 packets for their efforts. Groups like the Seed Savers Exchange allow you to purchase seed without becoming a member, but membership has its perks….lots of information, discounts and member’s only offerings, plus you’re supporting an important organization.

There’s a lot to know about collecting seed, but it is beyond the scope of this blog post to get into a lot of detail.  Besides, there is so much information now on the internet that you no doubt will find  answers to particular seed questions in a web search. I just want to pass on some basic tips.

  • Collect seed on a sunny dry day. Wet seed pods can harbor spores which may encourage mold ands spoil the seed.
  • Label your seed correctly, especially if you plan to donate to a seed exchange.
  • If you grow several varieties of certain plant and they are within close range  of each other (for example: several different forms/colors of zinnias) your seed will not come true to type. You may get some interesting variations and colors, but you should label it as such. Also, seed from most F1 Hybrids will not come true.
  • Watch seed pods daily for maturity. You want to capture them just before they explode all over your garden.
  • Store the seed in paper bags in a dry spot until you have time to clean and sort.
  • Separate the chaff from the seed when packaging.

Here are  links for more information on joining a few Plant Societies.

The Hardy Plant Society–Mid Atlantic Group

The Hardy Plant Society–UK

North American Rock Garden Society

The Seed Savers Exchange

A Dreaded Chore: Repotting an Agave

sad, sad Agave

I’ll confess. I had avoided repotting (for almost a year now) what had become one very sad looking Agave.  The older leaves had become brown and ugly, and obnoxious weeds had taken root. The piercing tips and teeth on the leaves looked ferocious, and I didn’t want to give blood. So there it sat, in a neglected corner, a woeful sight indeed.

As we were gathering all the tender plants to bring inside for the winter, it was time to make a choice about whether to save or toss the misbegotten Agave. A decision was made: yes, save it. A plant that has the will to carry on despite such neglect deserves not only respect; it deserves admiration. And as it turned out, grooming and repotting wasn’t a big deal after all. Here’s how we went about it:

The first thing to do is put on some protective gloves. Carefully remove the Agave from its pot, standing over a wheelbarrow or large receptacle to catch the debris. Tilt the plant so you can get at the base of the crown with your clippers and remove the dried up foliage. Next, loosen up the soil around the roots and remove any weeds that may have established, teasing out their roots so they won’t make a comeback.

Use a very well drained soil mix amended with sand and perlite, and if you have access to grit or gravel, add some too. (We don’t add fertilizer, since Agave are very light feeders. Instead, we liquid feed with fish emuslion/seaweed 2 or 3 times a year.) Position the Agave in the center of the pot, and then backfill. The repotting is accomplished, and we can now place the Agave in a spot where it merits attention.

carefully remove old leaves

loosening the roots

Agave, happier looking now

 

Weeping with Wisteria…

Wisteria floribunda 'Blue Eyes'It’s the third week in May, and the Wisteria floribunda ‘Blue Eyes’ which covers our pergola has begun to drip with fragrant blossoms. It’s certainly a sight, and elicits ooh’s and ahh’s from nursery visitors. Conversation immediately turns to pruning advice, and the question we hear over and over again, “Why hasn’t my Wisteria ever bloomed?”

We’ll cover extensive pruning Wisteria advice in a later blog posting, but let me address the flowering question. Wisteria often take several years to bloom after transplanting as it  is concentrating energy on establishing a firm root system, but there are other points to consider. First, plants should receive a good 6 hours or more of sunlight. Also, do not fertilize with a high nitrogen fertilizer. Wisteria are in the legume family, and fix their own nitrogen from soil. Select a fertilizer with a high phosphorus # (the middle number) such as 5-10-10, 5-10-5, or  Espoma’s FlowerTone which is a 3-4-5.

It is advisable to select named clones which have been propagated from productive flowering stock. Wisteria grown from seed are quite variable in their blossom production, and some have been known to never produce a bud. Another thing to consider is that Wisteria sets buds on old wood, and should be pruned  in late spring after flowering (or when it should have flowered) to about 6″ from main branches. One other trick is root pruning in early spring. Using a sharp a spade, dig in about a 2′ radius from the base of the vine. This will sever the roots and may shock the plants into flowering.

Pruning 301

This is the third in a series of blogs preceding our upcoming pruning workshop.  Today we’ll examine growth habits and regenerative responses.  Make the most of our upcoming workshop but reading through this series of blogs first.  For questions, address Chris @ ctracey@avantgardensne.com.
 Let’s review each of our five plant categories:
Chamaecyparis o. 'Fernspray'

Semi-open Form Conifer

Deciduous Conifers– This group produces a central leader. A central leader is a single trunk headed straight up to the sky. Structurally, this is the best of all growth habits.  It is pretty much impossible to prune them into any other form; they will always revert to a single leader. Their branching is symmetrical. This group regenerates well because of the dormant buds present throughout the trunk (old wood).

Evergreen Conifers– Of the tree forms, some naturally produce a central leader while others produce multiple leaders.  Most can be trained to a central leader if you have the patience and start training them in their youth.  Multiple leaders have the tendency to spread apart under snow and wind loads.  This group does not regenerate well because dormant buds are not present on old wood. Small shrubs forms of evergreen conifers will be addressed in the workshop.

Boxwood

Closed Form…Boxwood

Broad Leaf Evergreens- Most are multi-stemmed  and should be left that way. These produce many stems from the base as well as many primary, secondary and tertiary branches.  This group regenerates well; they will sprout from old wood, when damaged or presented with more sunlight as dormant buds exist throughout.

Clethra barbinervis form

Open Form of Deciduous Shrub/Tree

Deciduous Trees-Some naturally produce a central leader while others produce multiple leaders.  Most can be trained to a central leader if you have the patience and start training them in their youth.  Although snow and wind loads are not as detrimental to this group, they have greater stuctural integrity as single leader specimens.  Most have strong regenerative response to pruning, damage and increased light exposure.

Deciduous Shrubs-Most are multi-stemmed  and should be left that way. These have strong regenerative properties and can be cut back as far as you’d like (if you don?t mind foregoing a years blossoms).

In general, Alternate branching plants are easier to prune into “open forms” by a process called thinning out (think apple trees in an orchard or well-tended Tea Roses), but don’t respond as well to  extensive tipping back (shearing), which produces that scrumptious chicken croquette shape.  The exception to this occurs when the alternate branching pattern has short internodal spacing (the distance between one branch and the next is very short). Many evergreens such as boxwood, yews, and arborvitae produce closed forms without any help from shears because of their short internodal spacing. Opposite branching plants generally take more work to prune into open forms, but in many instances it is worth the effort.   This branching habit tends to produce  a “closed form” and shearing only intensifies this, often resulting in the “cartoon strong man form”, all upper body with skinny little legs.

Pruning Basics: 201

This is the second in a series of blog posts leading up to our April 17, 2011 pruning workshop.  These posts will address things you should be familiar with before you take pruners to plants.  If you’ve signed up for the workshop, we encourage you to read through blog posts.

In the blog entry Pruning 101,  you were asked to identify the plants you are intersted in pruning.  With plant names now in hand, you next need  to decide which of the following woody plant groups your tree/shrub falls under.

Opposite Branching

  • Conifers deciduous e. g.  Larix (Larch), Metasequoia (Dawn Redwood), Taxodium (Bald Pond Cypress)
  • Conifersevergreen e. g. Pinus (Pine), Picea (Spruce) Abies (Fir)
  • Broad Leaf Evergreen e. g. Rhododendron, Ilex (Holly), Pieris (Andromeda)
  • Deciduous Tree e. g. Acer (maple), Quercus (Oak), Stewartia, Fagus (Beech)
  • Deciduous Shrub e. g. Rosa (Rose), Viburnum, Salix (Willow), Spirea, Vaccinium (Blueberry), Lavandula (Lavender)

These 5 groups are your launching off point: each embodies of group of plants that generally have specific growth/branching habits and regenerative responses/capabilities.  We will leave the regenerative processes for the next blog.

alternate branches

Alternate Branches

Growth and branching habits are responsible for growth patterns in all plants and they fall under one of two groups,  alternate or oppositeAlternate branching occurs when only one new shoot/leaf node develops along a plant limb at any given point while the next developing shoot/leaf node occurs at a different point on the opposite side of the limb-see example. Opposite branching occurs when two new shoots/ leaf nodes develop at the same point along a limb, but on opposite sides of the limb-see example.  Although the examples here are clear, it is often less so because there can be a considerable amount of variation.  Make an attempt to differentiate these patterns on your own plants, while noting their variability.  We will examine what this variability means to the pruning process when regenerative responses are discussed in the next posting.

Pruning Basics 101

This will be the first in a series of blogs leading up to our April 17, 2011 pruning workshop. That stated, this article will help everyone on there way to pruning, even if they can?t join in the fun on April 17th. These blog posts will address things you should be familiar with before you take pruners to plants.  Make the most of our upcoming workshop by reading through thisseries of  blog posts. For questions, address Chris at  ctracey@avantgardensne.com.

Styrax japonica in winter

Every plant has a name, both Latin and common. For a beginner, knowing one or the other is crucial. If you don’t know either, then it’s impossible for any professional to tell you how to prune it. Photographs will help to identify it. Let’s assume it is the off seasons, late fall through early spring, when all our deciduous plants are posing unclothed, their bare limbs shivering. You will snap 2 or 3 photos: one of the entire plant, and one of an individual 8 -12″ section of an outer limb, and perhaps one of the trunk or base of the plant.  If you think that the bark or the terminal buds (the very end of the branches) is unique, than snap a photo of that too. Make notes about anything you recall it doing in the previous year, e. g. “It bloomed white on Mother’s Day” or “the fall color was butter yellow”.  Send this information to Avant Gardens (or a good local nursery) via email and we’ll help you out (you might want to reference this blog to let us know you’re not sending spam; we get nervous opening up attachments from senders we don”t know). Don’t be shy. People in the plant trade love to share information!

If the growing season has begun and  plants have leafed out, take three photographs: one of the whole plant, one of the plant in flower (if it does bloom), and one showing a small segment of branch with leaves attached. Does your plant has some other distinction, like mottled bark, unique cones, columnar habit, scent, etc? Snap that picture or make  notate these observations.  Make note of anything you remember about that plant that will help identify it. ( A note that your mother-in-law gave it to you probably won’t aid in identifying it, unless of course she remembers what it is– and it is not a problem to ask her. )  Remember that you can always ask us at Avant Gardens or check your local nursery.

Examples of helpful shots are:

Styrax bark

Chamaecyparis obtusa ‘Fernleaf Gold’

Chamaecyparis branch

Seed Collecting Tips

Clockwise from top left: Paeonia obovata, Amsonia hubrictii, Aster laeve, Nicotiana knightiana

The most frequently asked question regarding seed collecting is How do I know if seed is ripe?” Here’s a very general answer, for seeds of different plants ripen at different times, and their appearance, when ripe, can be as different as the individual plants that produced them. You need to keep a watchful eye. Observe the green immature pods over time, and suddenly you’ll notice brown seed capsules ready to split and burst. If you are not vigilant, you may discover empty seed pods days later, and your opportunity will have passed. (You can also try placing a paper bag over the immature seed capsule and securing it with string. When the seed ripens it will be contained in the bag.)

Collecting Tips: Mature seeds are usually dark in color, firm, and dry. Seeds that are green and moist are usually immature and generally will not germinate or will produce unhealthy seedlings. The flesh of pulpy fruits often becomes soft and changes from green/yellow, to red or blue-purple when ripe.

Cleaning: In a cool dry space, place dry seed capsules in a paper bag secured with string and hang upside down.  Clustered seeds of composite plants such as Asters and Marigolds might benefit from being laid out on newspaper layers and allowed to dry more completely. Remove the chaff and other vegetable matter which may harbor fungal spores which will spread and infect the seeds. Moist seed from fleshy fruit such as tomatoes, or from ornamentals such as Arisaema, should have the mucilage (the wet medium surrounding seed) rinsed off. Place the ripened seed in a sieve and rinse off thoroughly. Spread rinsed seed on layers of newspaper and allow to air dry.

Storage: Only store cleaned and dry seed. The combination of moisture and warmth will cause spoilage. Store seed in paper envelopes or bags to allow them to breathe. Don’t use plastic baggies, which may trap moisture. Keep your seeds in a cool dark dry space. Your refrigerator would work, if you have room, or perhaps a closet or cabinet in a cool room. Clearly label all packets with all pertinent information.

Important: Remember the lower the humidity and temperature in storage, the longer the viability of the stored seed

For more info online: http://theseedsite.co.uk/harvesting.html If you really want the specifics, you need the seed germinating bible. Norman Deno’s book Seed Germination, Theory and Practice can be purchased through the North American Rock Garden Society’s Bookstore.

Pruning Hydrangea

Hydrangea paniculata ‘Limelight’ blooms on new growth

Even seasoned gardeners seem to be confused as to when to prune Hydrangea.

Begin by identifying which Hydrangea species you are growing, to determine whether it will bloom on new growth or on old wood (last year’s stalks). The species arborescens, paniculata and some newer forms of macrophylla bloom on new wood. All the Hydrangea macrophylla (Mophead and Lacecap types) and quercifolia (Oakleaf)  bloom on old wood, as long as there isn’t winter damage. Next year?s blossoms are set on the upper portion of the woody stalks in late summer and fall. H. macrophylla selections should not be pruned until after the plants have leafed out. In late spring, prune out or tip back any dead wood for a clean appearance.

The hardiest and most foolproof of all the Hydrangea are the paniculata group (Pee Gee types) and the arborescens group (Smooth Hydrangea). Both of these species can be cut within inches of the ground each spring if you want to control the size of your plants.  They stalks can always be thinned to improve plant shape, and there is no harm to next year’s display if you want to cut long stemmed bouquets in summer and fall.

There are a lot of new Hydrangea macrophylla selections on the market, including ‘Double Expressions’, ‘Red Sensation’, ‘Let’s Dance Starlight’, and ‘Endless Summer’ that bloom on old and new wood. The blossoms appearing on old growth will display in early summer, while the flowers that form on new growth will appear later in August and September, for a long continuous display. If you live in the colder parts of zone 6 or zone 5, you may get too much winterkill for blossoms on the old growth, but you will still be able to enjoy a late summer through fall display.