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Breeding Hardy Rhododendrons in Finland
Kristian Theqvist, 16-Apr-2016, rev. 028

Pollinating

Elepidotes


Explanations of the symbols in the table

02 OK crossing done in 2002 and germination was succesful
02 F crossing done in 2002 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
03 OK crossing done in 2003 and germination was succesful
03 F crossing done in 2003 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
04 OK crossing done in 2004 and germination was succesful
04 F crossing done in 2004 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
05 OK crossing done in 2005 and germination was succesful
05 F crossing done in 2005 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
06 OK crossing done in 2006 and germination was succesful
06 F crossing done in 2006 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
07 OK crossing done in 2007 and germination was succesful
07 F crossing done in 2007 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
08 OK crossing done in 2008 and germination was succesful
08 F crossing done in 2008 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
09 OK crossing done in 2009 and germination was succesful
09 F crossing done in 2009 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
10 OK crossing done in 2010 and germination was succesful
10 F crossing done in 2010 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
11 OK crossing done in 2011 and germination was succesful
11 F crossing done in 2011 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
12 OK crossing done in 2012 and germination was succesful
12 F crossing done in 2012 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
13 OK crossing done in 2013 and germination was succesful
13 F crossing done in 2013 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)
15 OK crossing done in 2013 and germination was succesful
15 F crossing done in 2013 but germination failed (sterile pollen, not enough pollen, pollen not good, bad timing in pollination, polyploidy, ..)

Elepidote crossings table 1, pollen from species

Pollen \ Mother 'Elviira' 'Mauritz' 'Kullervo' 'Haaga' 'Helsinki University' 'Mikkeli' 'P.M.A. Tigerstedt' 'Pekka' 'Hellikki' 'Elsie Maria' 'Eino'
adenogynum           15 OK          
adenopodum     04 OK     04 OK          
annae             06 F        
anwheiense     04 OK     04 OK          
arboreum ssp. arboreum           12 OK   12 OK 12 OK    
arizelum RSF 1965/335             07 OK (1) 07 OK      
auriculatum RSF 1967/698             07 OK        
barbatum   12 OK           12 OK 12 OK    
barbatum RSF 1965/304           08 OK     08 OK    
brachycarpum x aureum             03 OK        
bureavii 03 OK   03 F, 04 F 03 F   03 F, 04 F          
bureavii RSF 1999/692     09 OK     09 OK   09 OK      
calophytum         06 OK     06 OK      
campanulatum     04 OK 03 OK   04 OK          
campylocarpum var. elatum     05 OK     05 OK 05 OK     05 OK  
catacosmum RSF 1967/689   08 OK 08 OK                
chamaethomsonii   15 OK                  
clementinae     04 F     04 F          
crinigerum     12 OK     12 OK          
decorum         03 OK 06 OK   06 OK      
denudatum           13 OK   13 OK      
dichroanthum var. scyphocalyx     06 F             06 OK  
dichroanthum 'Böhmen' 03 OK   02 OK 04 OK 02 OK 02 OK, 11 OK 04 OK 05 OK  05 F, 12 OK  04 OK  
eudoxum 04 F               04 F    
faberi           06 OK          
forrestii var. repens 06 OK               06 OK    
fortunei     04 OK 04 OK   04 OK 04 OK 04 OK      
fulvum     05 F     05 F 05 OK 05 OK      
grande RSF 1971/338         07 OK     07 OK      
griffithianum         12 OK 12 OK   12 OK      
haematodes 03 F 12 F 03 F   03 F   03 F   03 F, 12 F    
habrotrichum RSF 1983/052           07 OK          
hemsleyanum           06 OK   06 OK   06 OK  
hodgsonii RSF 1976/191   09 OK 09 OK       09 OK 09 OK 09 OK    
hodgsonii, Milde Arboretum           15 OK          
huianum   13 OK   13 OK   13 OK   13 OK   13 OK  
insigne           06 OK 06 OK 06 OK      
irroratum 'Polka Dot' RSF 1969/073     09 OK     09 OK 09 OK        
kesangiae RSF 1991/071           07 OK   07 OK      
lacteum RSF 1975/125             07 OK        
lacteum           13 OK       13 OK  
lanigerum RSF 1975/114           08 F 08 OK   08 F    
longesquamatum         06 OK 06 OK 06 OK 06 OK      
macabeanum         12 OK 12 OK   12 OK      
macabeanum RSF 1975/052           08 OK 08 OK 08 OK      
magnificum RSF 1981/080         07 OK 07 OK 07 OK        
makinoi 03 OK   03 OK 03 OK 04 F 03 OK 04 OK 03 OK      
mallotum RSF 1966/557   08 F 08 F           08 F    
mallotum RSF 2004/049   09 OK         09 OK   09 OK    
microgynum   15 OK                  
montroseanum RSF 1982/043           08 F 08 OK 08 F      
nakotiltum           11 OK          
niveum   13 OK   13 OK   13 OK          
ochraceum           10 OK     10 OK 10 OK  
oreodoxa     05 F     05 F 05 OK        
oreodoxa var. fargesii     05 F 05 F   05 F 05 OK 05 F      
pachysanthum RSF 1993/043     09 OK     09 OK          
prattii         06 OK 06 OK 06 OK 06 OK      
prattii           10 OK   10 OK      
pronum RSF 1974/047     08 OK     08 OK          
recurvoides RSF 1974/099     09 OK     09 OK          
rex 06 OK   05 OK 05 OK   05 OK 05 OK 05 OK   05 F  
rex ssp. fictolacteum           15 OK          
rex ssp. rex       13 OK       13 OK      
ririei             06 OK        
rotschildii RSF 1975/182         07 OK 07 OK 07 OK 07 OK      
roxieanum var. oreonastes           15 OK          
sanguineum var. didymum     08 OK     10 OK   08 OK   06 OK 10 OK
sinofalconeri RSF 2000/151           07 OK 07 OK (1)        
sinogrande RSF 1982/040           09 OK 09 OK 09 OK      
strigillosum 05 F, 06 OK         05 OK 05 OK   05 OK    
taliense     06 F   06 OK 06 OK 06 OK 06 OK      
temenium 04 OK               04 OK    
thomsonii                 06 OK 06 OK  
traillianum     06 F     06 OK 06 OK 06 OK      
uvarifolium     04 OK   04 OK 04 F, 10 OK 10 OK 04 OK      
venator   12 OK       12 OK     12 OK    
vernicosum       04 OK 04 OK            
wasonii   15 F                  
wightii           04 OK 04 OK        
williamsianum   13 OK                  
wiltonii 03 F   03 F 03 F   03 F   03 F      
yakushimanum 'Edelweiss'         02 OK            
yakushimanum 'Ken Janeck'     02 OK   02 OK 03 OK   03 OK      
yakushimanum 'Mist Maiden'     02 OK   02 OK 02 OK          
yuefengense   13 OK   13 OK   13 OK   13 OK      

Total crosses OK with species

7 8 20 10 16 54 31 33 13 9 1
Pollen \ Mother 'Elviira' 'Mauritz' 'Kullervo' 'Haaga' 'Helsinki University' 'Mikkeli' 'P.M.A. Tigerstedt' 'Pekka' 'Hellikki' 'Elsie Maria' 'Eino'

(1) Annoying mixup in pollination or marking. Pollen could be either from arizelum or sinofalconeri.

Elepidote crossings table 2, pollen from hybrid

Pollen \ Mother 'Elviira' 'Mauritz' 'Kullervo' 'Haaga' 'Helsinki University' 'Mikkeli' 'P.M.A. Tigerstedt' 'Pekka' 'Hellikki' 'Elsie Maria' 'Eino'
'America' 03 F               03 OK    
'Bad Eilsen' 04 F, 06 OK               04 F    
'Blue Bell' 03 OK   03 F   03 OK 03 OK 03 OK        
brachycarpum var. tigerstedtii x barbatum by Kaarel Voitk               09 OK 09 OK    
BVTrex-01, brachycarpum var. tigerstedtii x rex by Kaarel Voitk           12 OK          
'Brigitte', insigne hybrid           05 OK          
bureavii hybrid, Bjarne Dinesen     05 F 05 OK   05 F 05 OK 05 OK      
'Burgundula'                     10 OK
'Busuki'           15 OK          
'Calsap', catawbiense hybrid     02 OK   02 OK 02 OK 06 OK        
'Cherry Kiss'           11 OK     12 OK    
'Christian'         10 OK 10 OK       10 OK  
'Corinna', repens hybrid 03 F                    
'Crete', yaku x smirnowii hybrid     04 OK     04 OK          
'Dagmar', decorum hybrid     02 OK   02 OK 02 OK          
dichroanthum hybrid 'Medusa' 03 OK   03 OK 03 F     03 OK        
'Django', brachycarpum hybrid 03 F   02 F   02 F 03 F 02 F          
'Edeltraud'             03 OK 03 OK      
'Elsie Maria', dichroanthum hybrid     02 OK   02 OK 02 OK       05 OK  
'Ever Red' 06 OK               06 OK 06 OK  
'Flautando'       13 OK         13 OK 13 OK  
'Fred Wynniatt'       03 OK   03 OK          
'Golden Coach'     03 OK   03 OK 03 OK 03 OK        
'Goldschatz' = 'Goldprinz'     03 F, 04 OK 04 OK   04 OK 03 F, 04 OK 04 OK 10 OK 04 OK  
'Goldsworth Orange'     12 OK     11 OK          
'Gradito', smirnowii hybrid         02 OK            
'Great Dane', yaku x rex  hybrid 03 OK   03 F, 04 F 03 OK   03 OK   03 OK      
griersonianum hybrid, Bjarne Dinesen             06 OK   06 OK 06 OK  
haematodes hybrid, Bjarne Dinesen 05 F, 06 OK   05 OK       05 OK   05 OK    
'Harold Amateis', maximum x strigillosum hybrid 05 F, 06 OK           05 OK   05 OK    
'Henry's Red'                 06 OK    
'Hydon Velvet', yakushimanum x bureavii hybrid     05 OK 05 OK   05 OK 05 OK 05 OK      
'Jens Jörgen Sörensen', makinoi hybrid 04 OK   04 OK   03 OK 03 OK 03 OK        
'Junifee'                   04 OK  
'Kalinka', yakushimanum hybrid     02 OK   02 OK 02 OK          
'King's Ride', insigne hybrid     04 OK     04 F, 05 OK 04 OK        
kyawii hybrid                 13 OK    
'Lavendelmilch', Azaleodendron         04 F   04 F        
'Lem's Monarch' 03 F         03 F   03 F, 10 OK 10 OK    
'Loderi Fairyland'           12 OK          
'Loderi King George'         12 OK     12 OK      
'Matador', griersonianum x strigillosum           10 OK     10 OK    
'Matterhorn'             04 OK        
'Morgenrot', yakushimanum hybrid                 05 OK    
'Mrs. Furnival'         03 OK   03 OK        
'Nancy Evans'           13 OK     13 F 13 F  
'Nathalie', smirnowii hybrid 06 F                    
'Paprika Spiced'     04 F       04 F        
'Pearce's American Beauty' 04 F, 06 F             04 F 04 F, 05 F    
'Rasputin'             06 OK   06 OK    
sanguineum x haematodes 06 OK               06 OK    
'Scintillation'             04 OK 04 F      
'Sonata' 03 F       03 F   03 F        
sutchuenense hybrid             08 OK        
sutchuenense var. geraldii x praevernum     04 OK     04 OK   04 OK      
'Top Banana' x dichroanthum ssp. scyphocalyx     04 OK       04 OK     04 OK  
'Viscy'         10 F 05 F  04 F 04 F, 05 F, 10 F   05 F  
'Vulcan'                 04 F, 05 F    
'Vulcan's Flame' 05 F               05 F    

Total crosses OK with hybrids

9   15 6 11 23 19 9 16 8 1
Pollen \ Mother 'Elviira' 'Mauritz' 'Kullervo' 'Haaga' 'Helsinki University' 'Mikkeli' 'P.M.A. Tigerstedt' 'Pekka' 'Hellikki' 'Elsie Maria' 'Eino'


Elepidote crossings table 3, statistics on species and hybrids combined

Pollen \ Mother 'Elviira' 'Mauritz' 'Kullervo' 'Haaga' 'Helsinki University' 'Mikkeli' 'P.M.A. Tigerstedt' 'Pekka' 'Hellikki' 'Elsie Maria' 'Eino' Sum
OK Crosses /
Total done in 2002
0 / 0 0 / 0 7 / 8 0 / 0 9 / 10 6 / 7 0 / 0 0 / 0 0 / 0 0 / 0 0 / 0 22 / 25
OK Crosses /
Total done in 2003
6 / 13 0 / 0 3 / 9 4 / 7 5 / 8 7 / 10 7 / 10 4 / 6 1 / 2 0 / 0 0 / 0 37 / 65
OK Crosses /
Total done in 2004
2 / 5 0 / 0 11 / 15 4 / 4 2 / 4 8 / 10 9 / 10 4 / 7 1 / 5 4 / 4 0 / 0 45 / 64
OK Crosses /
Total done in 2005
0 / 4 0 / 0 4 / 8 3 / 4 0 / 0 6 / 11 10 / 10 5 / 7 4 / 8 2 / 4 0 / 0 34 / 56
OK Crosses /
Total done in 2006
8 / 9 0 / 0 0 / 3 0 / 0 4 / 4 8 / 8 9 / 10 8 / 8 7 / 7 6 / 6 0 / 0 50 / 55
OK Crosses /
Total done in 2007
0 / 0 0 / 0 0 / 0 0 / 0 3 / 3 5 / 5 6 / 6 4 / 4 0 / 0 0 / 0 0 / 0 18 / 18
OK Crosses /
Total done in 2008
0 / 0 1 / 2 3 / 4 0 / 0 0 / 0 3 / 5 4 / 4 2 / 3 1 / 3 0 / 0 0 / 0 14 / 21
OK Crosses /
Total done in 2009
0 / 0 2 / 2 5 / 5 0 / 0 0 / 0 5 / 5 4 / 4 4 / 4 3 / 3 0 / 0 0 / 0 23 / 23

OK Crosses /
Total done in 2010

0 / 0 0 / 0 0 / 0 0 / 0 2 / 3 7 / 7 1 / 1 3 / 4 5 / 5 2 / 2 2 / 2 22 / 24
OK Crosses /
Total done in 2011
0 / 0 0 / 0 0 / 0 0 / 0 0 / 0 4 / 4 0 / 0 0 / 0 0 / 0 0 / 0 0 / 0 4 / 4
OK Crosses /
Total done in 2012
0 / 0 2 / 3 2 / 2 0 / 0 3 / 3 7 / 7 0 / 0 5 / 5 6 / 6 0 / 0 0 / 0 24 / 25
OK Crosses /
Total done in 2013
0 / 0 4 / 4 0 / 0 5 / 5 0 / 0 6 / 6 0 / 0 4 / 4 2 / 3 3 / 4 0 / 0 19 / 21
OK Crosses /
Total done in 2014
0 / 0 0 / 0 0 / 0 0 / 0 0 / 0 0 / 0 0 / 0 0 / 0 0 / 0 0 / 0 0 / 0 0 / 0
OK Crosses /
Total done in 2015
0 / 0 2 / 3 0 / 0 0 / 0 0 / 0 5 / 5 0 / 0 0 / 0 0 / 0 0 / 0 0 / 0 7 / 8
OK Crosses /
Total done all years
16 / 31 5 / 7 35 / 54 11 / 15 28 / 35 66 / 79 50 / 55 39 / 48 28 / 39 14 / 16 2 / 2 319 / 409

Note: The tables include only crossings with Finnish hybrids as mother. I have done also a lot of other elepidote crossings but they are not documented on these tables.


2003
In 2003 some of the collected pollen was not viable or there was not enough of it. In some cases I do suspect sterility, for example as in brachycarpum hybrid 'Django'. Another thing that may have affected the germination results is that I emasculated the flowers and applied pollen in 2003 probably a little bit too early when all of the stigmas were not yet receptive. Some ovaries did not start growing as expected.

2004
This is a learning process for me and in 2004 I had more patience to wait for the covered stigmas to be wet before I applied pollen. However, the weather was very cold in June and some pollinations probably failed partly because of too low temperature. This was specially the case with 'Elviira'. The temperature dropped to -6°C (21°F) on one of the nights after pollination.

2005 and 2006
In 2005 and 2006 I did continue the same line of hybridization work as in previous years. I have got pollen of several rhododendrons from Bjarne Dinesen (Denmark). Thanks Bjarne! See his marvelous pictures at Asperupgaard.

From 2002 to 2006 I've done 265 crosses in which the mother plant has been a hardy Finnish hybrid. Out of these 188 crosses have yielded seed.
I have high hopes that some of these could result in hybrids that have qualities worth for naming.

As of 22nd of November, 2006 I have myself 2277 plants cross plants growing and there are probably a lot more plants around the world from the seeds I've distributed to various Seed Exchanges.
Since my resources are limited (this is my hobby!) I sow only max 30 seeds per cross. This is not enough to get the whole variance of a cross. On the other hand this justifies the distribution of seeds to Seed Exchanges.

2007
In 2007 I made a lot less crosses than in previous years.
Based on the ARS Seed Exchange Pollen-to-Seed Program I ordered pollen from RSF and formed a small hybridizer team here in Finland. The two other hybridizers in addition to me were Osmo Jussila from Naantali and Jaakko Saarinen from Arboretum Mustila. To optimize the amount of seed we made R. brachycarpum var. tigerstedtii crosses with two separate plants, one at Naantali and another at Arboretum Mustila.
The main aim was to to get hardy big-leaf hybrids by using use the super hardy R. brachycarpum var. tigerstedtii and hardy proven Finnish hybrids as seed parent and pollen from big-leaf Rhododendron species. In addition there are side goals for yellow flowers, late flowering and good indumentum.
I have reported my own crosses on this page and other crosses of the hybridizer team on page The seed list for ARS 2008 Seed Exchange.

2008
Based on the Pollen-to-Seed Program I had formed in 2007 a small hybridizer team in Finland. The results in 2007 were good and the hybridization work was continued in 2008. The two other hybridizers in addition to Mr. Theqvist were Osmo Jussila from Naantali and Jaakko Saarinen from Arboretum Mustila. The main aim in the hybridization program was to to get hardy reds by using the super hardy R. brachycarpum var. tigerstedtii and hardy proven Finnish hybrids as seed parent and pollen from Rhododendron species with red flowers. In addition there were side goals for beautiful leaves and good indumentum. I have reported my own crosses with Finnish hybrids on this page and other crosses of the hybridizer team on page The seed list for ARS 2009 Seed Exchange.

2009
The hybrization team continued the third year in the ARS Seed Exchange Pollen-to-Seed Program. Each team member chose his favorite pollens from the RSF list. Results: The seed list for ARS 2010 Seed Exchange.

2010
The hybridization team decided not to participate in the Pollen-to-Seed Program due to personal workloads in other activities. I had also decided to reduce the number of crosses. However, on my travels I got some pollen and could not but make some 20 crosses for fun. I have added the crosses on the tables with the marking 10 OK or 10 F.

2011
I did make only 4 elepidote crosses in 2011 due to workload in other activities. I have thousands of plants growing from my crosses from previous years. The plants consume a lot of space in my arboretum and because of this I need to focus in new crosses only to the most interesting ones.

2012
I made in summer 2012 a total of 52 crosses on elepidotes and 42 crosses on azaleas. The list of seed giving crosses can be found from the page Seeds from summer 2012 to various Seed Exchanges.

2013
I made in summer 2013 a total of 35 crosses on elepidotes and 17 crosses on azaleas.

2014
I made in summer 2014 a total of 4 crosses on elepidotes and 8 on azaleas.

2015
I made in summer 2015 a total of 54 crosses on elepidotes and 9 on azaleas, but most crosses were now maternally on other than named Finnish cultivars.


Pictures and links to results

My Registered Rhododendron Hybrids
Unnamed or Non-registered Elepidote Hybrids

 

Pollen in small gelatin capsules
Figure 1. Pollen in small gelatin capsules.


Pollinated stigmas on 'Hlesinki University'
Figure 2. The seed pods on 'Helsinki University' are swelling. I got from Jens Birck an excellent idea of using Micropore Surgical Tape (3M) to protect the pollinated stigmas. I use the same tape to label the crosses with code numbers from my pollen database.


Helsinki_University x KTH-002
Figure 3. 'Helsinki University' x dichroanthum hybrid 'Elsie Maria' seed plant.


Helsinki_University x Calsap
Figure 4. 'Helsinki University' x 'Calsap' seed plant.


Kullervo x Ken Janeck
Figure 5. 'Kullervo' x 'Ken Janeck' seed plant with variegated leaves.


Cold frame
Figure 6. The seed plants need good protection for their first winter. This 9-window cold frame can take some 2000 seed plants. I have another cold frame for large but tender plants.


Small plants on the field
Figure 7. The rhododendron plants have been planted in rows for their second winter. They are shaded with a green net and get sprinkled water (Netafim) on dry summer weeks.


Small plants on the field
Figure 8. 'Mikkeli' x makinoi cross plants have usually long and narrow leaves typical to makinoi.

 

Summer 2008: I have been pleased to see great variability and interesting leaf forms in the hybrids.
Pictures on Rhododendron hybrid plants, leaf forms and growth habits in 2008


Summer 2009
: Several hybrids have flowered for the first time. Most have as expected non-interesting pink flowers or miniature flowers.
However, there are a couple of plants that may be worth a small volume propagation for testing in various climatic conditions.

Small plants on the field
Figure 9. 'Kullervo' x 'Golden Coach' cross gave nice looking flowers.

More pictures and information on this and other hybrids: Unnamed or Non-registered Elepidote Hybrids


I'll report on the progress of the seed plants on this page whenever something worthwhile reporting happens.

Lepidote Crosses in 2003 using R. tomentosum as Seed Plant
Pollinations in 2004 using R. tomentosum as Seed Plant
Pollinations in 2005 using R. tomentosum as Seed Plant
Pollinations in 2006 using R. tomentosum as Seed Plant