Planting with the Seasons (Indigo Salvia and Ageratum)

Question from Diane:
Good morning, Pat. I last wrote to you in July, when I asked what to put on the fence at my Hancock Park house with the new neighbors. We took your advice with the Jasmine and added in some iceberg roses as an experiment. All seems to be going well and I thank you for that suggestion.

I am done landscaping my garden and going into my first winter. I have sent you a few pictures of what I call my faux-English garden. This is north facing side of the garden. I have a formal vegetable garden on the south facing side but that is for another email….

I got your book last week and quickly learned that I have to read months in advance to know where I am to go. I’m trying to plant from seed but have figured out I need to start two months earlier than I think I do. In August, I planted 150 ornamental kale seeds for the front of the house and wouldn’t you know, I needed 200! I just killed me to go by another flat. Your book is terrific and I am right now pouring over December and January. I have put in the 200 ranunculus and anemones, with a border of English Daisies. Broccoli and lettuce and peas are all up and this weekend I’m going to try your fast way to grow carrots, with the hot water. I passed on the strawberries until next year but am going with some raspberries and blueberries.

Anyway, to my question…In my border – see picture 20101023 – the salvia and especially the ageratum is big and healthy. Will it last through the winter? Should / could I cut it back and it will bloom again in the spring? The ageratum is reseeding itself. I want the path to look pretty in the spring and have tucked in some primroses behind the ageratum. I was thinking of taking out the salvia and replacing it with stock. Your thoughts?

I hope you don’t mind my writing and asking questions. If you don’t, I’ll probably have more as I go along, month by month.

Answer from Pat:
Thank you so much for telling me about the results of our last correspondence and for the lovely photos. You have done a great job with your design and execution. No of course I don’t mind if you ask me questions from time to time. It’s great when they are on another subject since that makes for a new heading that other gardeners can find through Google.

Be sure to shear the front of the star jasmine(Trachelospermum jasminioides) after bloom every year so you can keep it basically the same size and flat in front and so it does not get too thick and woody and eat up all your room you need for flowers. I hope you bought tall star jasmine on trellis. Even the short ones will eventually grow tall unless pruned but it will take many years. Never cut back the tips until it’s as tall as you want so that it effectively covers the wire fence. If you cut back the tips before it is tall enough it may take many years to grow tall. (It’s a little hard to tell from the photo which plants are the star jasmine since there is something else with woody stems and larger leaves, perhaps Texas privet (Ligustrum japonicum ‘Texanum’.) If this is what it is it will also need clipping and pinching back to keep flat and bushy ang preserve room for flowers in front. Also its roots may eventually compete with your flowers, whereas star jasmine is less of a problem that way.

I see a fern. Be sure it is not southern sword fern (Nephrolepis cordifolia)—I don’t think it is, but if you have some in your garden yank it out now before it spreads! Southern sword fern is a perfect plant to put in a narrow confined bed between a brick patio and a wall, for example, where it will be easy and look nice forever and never escape. But once southern sword fern gets going in a bed with other plantss it takes over, chokes other things out, and is then impossible to get rid of without pulling out all the other plants and starting over. It is a plant people often give to each other and woe betide the gardener who accepts it, despite the fact it is very attractive and easy. I am currently in the process of tearing it out of an island bed and fear that a number of good plants will be sacrificed in the process. Last time we did this I lost a treasured and irreplaceable rose (no longer in the trade and impossible to find), but we are into a whole re-design and re-building in that part of the garden so this provides a perfect opportunity to start over without that thug of a fern.

I am so interested in all you told me. It sounds as if you are planting perfectly with the seasons in the vegetable garden and have gotten into the right rhythm there, but as you pointed out you needed to begin in August to get enough cabbage and kale plants from seeds. Tall varieties of stock (Matthiola incana) also need to be started in flats in August from seeds. Years ago I took great joy in growing stock as a cut flower, but it is too late now to start. Plant it another year. Also I used to grow tall foxgloves from seeds in flats and then plant out in the garden. Fine nurseries sometimes carry transplants in fall but usually it is ‘Foxy’, a short plant and not truly a biennial. There is no point in your planting the dwarf stock you find in nurseries since it is prone to pests and diseases and flowers are not long lasting. There are better things. So wait until next year and plant stock in flats in August 2011.

No, if you planted floss flower in late spring or early summer (Ageratum houstonianum) you really cannot keep it all winter. Ageratum is an annual flower which means that it is just good for one season. You have vinca. That is a summer annual too. Hancock Park is in the Los Angeles Basin and when it gets cold that will put the kibosh on your ageratum and vinca. You mention Indigo Salvia. Do you mean Salvia ‘Indigo Spires’. That usually grows taller and floppier than yours, but I had some once that fell down and looked like yours—very good in fact in fall. It is a tender perennial and not long lived. Both Salvia Indigo Spires and ageratum often look good in fall. You perhaps planted it a bit late and it’s all still going strong, including your white impatiens (impatiens is perennial but we treat it as an annual except in the mildest zones). These things won’t last all winter into spring looking as good as that.

What you have really created is an annual flower bed and you need to tear a lot of stuff out now and replant it with cool-season flowers for winter and spring. If you get them into bloom before Christmas they will bloom all winter into spring. There is an art to planting and maintaining an annual flower bed and it is a very easy and fun way to garden. I did it for years but it seems as if many gardeners have forgotten how, though my book explains it in detail. The most important part of it is you totally revamp the bed twice a year, spring and fall (October and June usually is the best way). Tear out all the warm-season annuals in October or early November (even if they are still going strong), dig up the bed, work aged compost into the top foot and organic fertilizer for flowers into the top 6 or 8 inches and then totally replant with cool-season flowers like pansies, English primroses, malacoides primroses, obconica primroses, Iceland poppies, hollyhock (choose a rust -free variety), stock, foxgloves, dianthus, nemesia strumosa, snap dragons, tall cineraria—Plant cineraria in “skyshine”—a spot in shade from a building or tree but under the open sky is best for this plant—and yes bulbs like daffodils and ranunculus are perfect to mix in with all this too. Read October and September chapters for more suggestions for annual flowers to plant. It is not too late to catch up and do this now, though a little late, but next year you can adopt the proper rhythm. Most of the flowers I’ve mentioned can bloom all through winter and then give you the most spectacular April border you can imagine. (Some bloom mainly in spring but have to be planted now.) Then when the flowers fade as the weather warms up in late May or June, that’s the time to tear it out and prep the soil again like I said above and this time plant warm-season flowers for the heat of summer. You will love this and it’s easy and also cuts down on pests and diseases and problems and you can vary the color scheme from year to year and season to season. You don’t have to have blue and white forever and ever amen. By starting early you can also grow just about everything from seeds in flats to plant out later. I had a friend who even planted ‘Charms’ dianthus in flats in August and planted big drifts of it in October, all from seeds. The same lady used candytuft as her edging. I prefer sweet alyssum since it’s longer blooming but gives much the same effect with less water and fuss and fewer snails.

Get into the rhythm of this and gardening will be easy. You will just work hard digging and planting for a couple of days in June and a couple of days in October and from then on all you do is deadhead or pick flowers!